Disc cartridge

ABSTRACT

A disc cartridge includes: a disc storage portion; first and second shutters provided on the bottom of the disc storage portion; and a rotational member interlocked with the shutters and having a disc supporting portion to support the disc thereon while the shutters are closed and a notch to be located inside a head opening while the shutters are opened. The shutters include disc holders for holding the disc thereon with the center of the disc offset from that of the disc storage portion such that an outer side surface of the disc contacts with the sidewall of the disc storage portion at a position where the notch is located while the shutters are closed. The inner circumference of a region, where the disc supporting portion contacts with the second side of the disc, defines a circle that has its center offset from the center of the disc storage portion.

TECHNICAL FIELD

[0001] The present invention relates to a disc cartridge for use to store a disk storage medium such as an optical disc or a magnetic disk therein in a rotatable state.

BACKGROUND ART

[0002] Various disc cartridges have been proposed as protective cases for disc storage media.

[0003] For example, Japanese Laid-Open Publication No. 9-153264 discloses a disc cartridge in which a disk storage medium having a single or double signal recording sides (which will be herein referred to as a “disc” simply) is completely enclosed in a disc storage portion. The disc storage portion is defined inside a cartridge body that is made up of upper and lower halves. The cartridge body includes chucking openings and a head opening. The chucking openings allow the turntable of a spindle motor and a damper to chuck a disc inserted, while the head opening allows a read/write head to read and/or write a signal from/on the disc. The lower one of the chucking openings is continuous with the head opening. Accordingly, while the user carries such a cartridge, dust easily enters the inside of the cartridge through these openings and the disc is also easily soiled with finger marks. For that reason, the disc cartridge further includes a shutter for closing these openings up.

[0004] A disc cartridge having such a structure, however, has the following drawbacks. Firstly, such a disc cartridge cannot be so thin. This is because the disc storage space, defined between the upper and lower halves, should be thick enough to allow a disc drive to accurately read or write a signal (or information) from/onto the disc stored in such a disc cartridge. The reasons why the disc storage space should be relatively thick include the expected flutter or warp of the disc being rotated and an error that may occur in disposing the disc cartridge at a predetermined position inside the disc drive.

[0005] Secondly, the shutter for closing up these chucking and head openings at the same time cannot be formed at a low cost, thus increasing the overall manufacturing cost of such a disc cartridge. The reason is as follows. Specifically, the lower half of the disc cartridge is provided with a chucking opening for the turntable of the spindle motor and a head opening, while the upper half thereof is provided with another chucking opening for the clamper. Thus, to close these three openings up at a time, the shutter needs to be formed in a U-shape, which is not so cheap to make.

[0006] Thirdly, the disc stored inside such a disc cartridge is not fixed in many cases, thus possibly causing dust or fine particle deposition and scratching problems. Specifically, although a disc with a metal hub can be attracted and fixed in position via a magnetic force so as not to move inconstantly, an optical disc with no hub, e.g., a CD or a DVD, is normally not fixed, and movable freely, inside the disc cartridge. Accordingly, when the shutter of the disc cartridge is opened inside the disc drive, dust may enter the cartridge through its openings and be deposited on the disc easily. Also, if the disc is shaken so much as to contact with the inner walls of the disc cartridge, the signal recording side of the disc may get scratched or fine particles may be stirred up and deposited on the disc.

DISCLOSURE OF INVENTION

[0007] In order to overcome the problems described above, an object of the present invention is to provide a disc cartridge that has a reduced thickness and a simplified, much less expensive shutter for a single-sided disc, in particular.

[0008] Another object of the present invention is to provide a disc cartridge that can drastically reduce the dust to be deposited on the disc stored therein by getting the disc firmly held inside the disc cartridge and eliminating the inconstant movement of the disc.

[0009] A third object of the present invention is to provide a disc cartridge of a good design by displaying the label side of the disc stored therein.

[0010] A disc cartridge according to a preferred embodiment of the present invention preferably includes a cartridge body, first and second shutters, and a rotational member. The cartridge body preferably includes a disc storage portion, a chucking opening and a head opening. The disc storage portion preferably has a disc window and a bottom and preferably stores a disc, having first and second sides, therein so that the disc is rotatable in the disc storage portion and that the first side of the disc is exposed inside the disc window. The chucking opening is preferably formed on the bottom of the disc storage portion so as to get the disc chucked externally. The head opening is also preferably formed on the bottom of the disc storage portion so as to allow a head, which reads and/or writes a signal from/on the second side of the disc, to access the second side of the disc. The first and second shutters are preferably provided on the bottom of the disc storage portion for the purpose of exposing or covering the head opening. The rotational member is preferably provided over the first and second shutters inside the disc storage portion and preferably rotates as the first and second shutters are opened or closed. The rotational member preferably includes a disc supporting portion and a notch. The disc supporting portion preferably contacts with an outer periphery of the second side of the disc while the first and second shutters are closed and thereby holds the disc thereon. The notch is preferably provided for the disc supporting portion so as to be located inside the head opening while the first and second shutters are opened. The disc storage portion preferably includes a sidewall along an outer periphery of the bottom. The first and second shutters preferably include disc holders for holding the disc thereon with the center of the disc offset from the center of the disc storage portion such that an outer side surface of the disc contacts with the sidewall of the disc storage portion at a position where the notch of the rotational member is located while the first and second shutters are closed. The inner circumference of a region, in which the disc supporting portion of the rotational member contacts with the second side of the disc, preferably defines a circle that has its center offset from the center of the disc storage portion.

[0011] In one preferred embodiment of the present invention, while the first and second shutters are closed, the center of the disc is preferably aligned with the center of the circle.

[0012] In another preferred embodiment of the present invention, while the first and second shutters are closed, a distance between the center of the disc and the center of the disc storage portion is preferably about 0.5 mm to about 1.5 mm.

[0013] In still another preferred embodiment, a portion of the sidewall of the disc storage portion, which contacts with the outer side surface of the disc, preferably has a radius of curvature that is substantially equal to that of the disc.

[0014] In yet another preferred embodiment, the other portion of the sidewall of the disc storage portion, which does not contact with the outer side surface of the disc, preferably has a radius of curvature that is greater than that of the disc.

[0015] A disc cartridge according to another preferred embodiment of the present invention preferably includes a cartridge body, first and second shutters, and a rotational member. The cartridge body preferably includes a disc storage portion, a chucking opening and a head opening. The disc storage portion preferably has a disc window and a bottom and preferably stores a disc, having first and second sides, therein so that the disc is rotatable in the disc storage portion and that the first side of the disc is exposed inside the disc window. The chucking opening is preferably formed on the bottom of the disc storage portion so as to get the disc chucked externally. The head opening is also preferably formed on the bottom of the disc storage portion so as to allow a head, which reads and/or writes a signal from/on the second side of the disc, to access the second side of the disc. The first and second shutters are preferably provided on the bottom of the disc storage portion for the purpose of exposing or covering the head opening. The rotational member is preferably provided over the first and second shutters inside the disc storage portion and preferably rotates as the first and second shutters are opened or closed. The rotational member preferably includes a disc supporting portion and a notch. The disc supporting portion preferably contacts with an outer periphery of the second side of the disc while the first and second shutters are closed and thereby holds the disc thereon. The notch is preferably provided for the disc supporting portion so as to be located inside the head opening while the first and second shutters are opened. The disc storage portion preferably includes a sidewall along an outer periphery of the bottom. One of the first and second shutters preferably includes a disc holder for applying an elastic force to the disc and holding the disc thereon such that an outer side surface of the disc contacts with the sidewall of the disc storage portion at a position where the notch of the rotational member is located while the first and second shutters are closed. The elastic force is preferably applied to the disc by deforming elastically the first or second shutter that includes the disc holder.

[0016] In one preferred embodiment of the present invention, the cartridge body preferably includes a recessed portion on the bottom of the disc storage portion. The first or second shutter that includes the disc holder is preferably deformed elastically near a sidewall that defines the recessed portion.

[0017] A disc cartridge according to still another preferred embodiment of the present invention preferably includes a cartridge body, at least one shutter, and a disc stopper. The cartridge body preferably includes a disc storage portion, a chucking opening and a head opening. The disc storage portion preferably has a disc window and a bottom and preferably stores a disc, having first and second sides, therein so that the disc is rotatable in the disc storage portion and that the first side of the disc is exposed inside the disc window. The chucking opening is preferably formed on the bottom of the disc storage portion so as to get the disc chucked externally. The head opening is also preferably formed on the bottom of the disc storage portion so as to allow a head, which reads and/or writes a signal from/on the second side of the disc, to access the second side of the disc. The shutter is preferably provided on the bottom of the disc storage portion for the purpose of exposing or covering the head opening. The disc stopper preferably has an arched concave side surface and is preferably supported by the cartridge body so as to be movable from a first position, at which the arched concave side surface protrudes over the disc that is stored inside the disc storage portion, to a second position, at which the arched concave side surface is not located over the disc, or vice versa.

[0018] In one preferred embodiment of the present invention, the arched concave side surface of the disc stopper preferably extends along a longer side of the disc stopper. The disc stopper may move from the first position to the second position, or vice versa, by sliding vertically to the longer side with respect to the cartridge body.

[0019] In an alternative preferred embodiment, the arched concave side surface of the disc stopper preferably extends along a longer side of the disc stopper. The disc stopper may move from the first position to the second position, or vice versa, by rotating on a shaft that extends parallelly to the longer side.

[0020] In another alternative preferred embodiment, the arched concave side surface of the disc stopper preferably extends along a longer side of the disc stopper. The disc stopper may move from the first position to the second position, or vice versa, by rotating on a shaft substantially parallelly to the first side of the disc. In that case, the shaft is preferably provided near one end of the longer side of the disc stopper.

[0021] In this particular preferred embodiment, the other end of the longer side of the disc stopper may be engaged with the cartridge body.

[0022] A disc cartridge according to yet another preferred embodiment of the present invention preferably includes a cartridge body, at least one shutter, a removal history hole, a cap member, and a disc stopper. The cartridge body preferably includes a disc storage portion, a chucking opening and a head opening. The disc storage portion preferably has a disc window and a bottom and preferably stores a disc, having first and second sides, therein so that the disc is rotatable in the disc storage portion and that the first side of the disc is exposed inside the disc window. The chucking opening is preferably formed on the bottom of the disc storage portion so as to get the disc chucked externally. The head opening is also preferably formed on the bottom of the disc storage portion so as to allow a head, which reads and/or writes a signal from/on the second side of the disc, to access the second side of the disc. The shutter is preferably provided on the bottom of the disc storage portion for the purpose of exposing or covering the head opening. The removal history hole is preferably provided for the cartridge body. The cap member preferably covers the removal history hole at least partially. The disc stopper is preferably supported by the cartridge body so as to be movable from a first position, at which the disc stopper protrudes over the disc that is stored inside the disc storage portion, to a second position, at which the disc stopper is not located over the disc, or vice versa. While the disc stopper is moving from the first position to the second position, the disc stopper preferably removes the cap member from the removal history hole.

[0023] In one preferred embodiment of the present invention, the disc stopper preferably moves from the first position to the second position, or vice versa, by rotating on a shaft substantially parallelly to the first side of the disc. The shaft is preferably provided near one end of the longer side of the disc stopper thereof. The center of rotation of the disc stopper is preferably aligned with the center of the removal history hole.

[0024] In this particular preferred embodiment, the cap member preferably has a columnar shape and preferably includes: connectors that are connected to an inner sidewall of the removal history hole; and a convex portion to engage with the disc stopper. The disc stopper preferably includes a concave portion that engages with the convex portion of the cap member.

[0025] More particularly, the center of the concave portion of the disc stopper is preferably aligned with the center of rotation of the disc stopper. By rotating the disc stopper, the cap member is rotated, the connectors are snapped off, and the cap member drops off from the removal history hole.

[0026] A disc cartridge according to yet another preferred embodiment of the present invention preferably includes a cartridge body, first and second shutters, a rotational member and a disc holder. The cartridge body preferably includes a disc storage portion, a chucking opening and a head opening. The disc storage portion preferably has a disc window and a bottom and preferably stores a disc, having first and second sides, therein so that the disc is rotatable in the disc storage portion and that the first side of the disc is exposed inside the disc window. The chucking opening is preferably formed on the bottom of the disc storage portion so as to get the disc chucked externally. The head opening is also preferably formed on the bottom of the disc storage portion so as to allow a head, which reads and/or writes a signal from/on the second side of the disc, to access the second side of the disc. The first and second shutters are preferably provided on the bottom of the disc storage portion for the purpose of exposing or covering the head opening. The rotational member is preferably provided over the first and second shutters inside the disc storage portion and is preferably interlocked with the first and second shutters in such a manner as to open or close the first and second shutters when rotates inside the disc storage portion. The disc holder preferably holds the disc thereon so as not to contact with a signal recording area on the second side of the disc while the first and second shutters are closed.

[0027] In one preferred embodiment of the present invention, supposing that a distance from the center of the disc to a first point on the second side of the disc is Rin; a distance from the center of the disc to a second point on the second side of the disc is Rout; a space having a height S needs to be provided under the second side of the disc; a first circle having a radius of Rout is defined on the second side of the disc; a second circle having a radius of (Rout—1.2 S) is defined on a plane that is separated from the second side by a distance of 0.3 S and parallel to the second side; and a third circle having a radius of (Rout—16.2 S) is defined on a plane that is separated from the second side by the distance S and parallel to the second side, the space is preferably obtained by removing a circular cylinder, having a bottom radius of Rin as measured from the center of the disc and the height S, from first and second truncated cones. The first point is located closer to the center of the disc than, and defined near, the inner periphery of the signal recording area while the first and second shutters are closed. The second point is located closer to an outer edge of the disc than, and defined near, the outer periphery of the signal recording area while the first and second shutters are closed. The bottom and top of the first truncated cone are defined by the first and second circles, respectively, while the bottom and top of the second truncated cone are defined by the second and third circles, respectively.

[0028] In this particular preferred embodiment, the height S of the space is preferably 1 mm, the bottom radius Rin of the circular cylinder is preferably 20 mm, and the radius Rout of the first circle is preferably 59 mm.

[0029] In another preferred embodiment, the rotational member preferably includes a disc supporting portion and a notch. The disc supporting portion preferably contacts with an outer periphery of the second side of the disc while the first and second shutters are closed and thereby holds the disc thereon. The notch is preferably provided for the disc supporting portion so as to be located inside the head opening while the first and second shutters are opened. The disc storage portion preferably includes a sidewall along an outer periphery of the bottom. The disc holder preferably holds the disc thereon with the center of the disc offset from the center of the disc storage portion such that an outer side surface of the disc contacts with the sidewall of the disc storage portion at a position where the notch of the rotational member is located while the first and second shutters are closed.

[0030] In this particular preferred embodiment, the disc supporting portion of the rotational member is preferably located at such a position as not to obstruct the space while the first and second shutters are closed.

[0031] In another preferred embodiment, the inner circumference of a region, in which the disc supporting portion of the rotational member contacts with the second side of the disc, preferably defines a circle that has its center offset from the center of the disc storage portion.

[0032] More particularly, while the first and second shutters are closed, the center of the disc is preferably aligned with the center of the circle.

[0033] In still another preferred embodiment, while the first and second shutters are closed, a distance between the center of the disc and the center of the disc storage portion is preferably about 0.5 mm to about 1.5 mm.

[0034] A disc cartridge according to yet another preferred embodiment of the present invention preferably includes a cartridge body, first and second shutters, a rotational member and a disc holder. The cartridge body preferably includes a disc storage portion, a chucking opening and a head opening. The disc storage portion preferably has a disc window and a bottom and preferably stores a disc, having first and second sides, therein so that the disc is rotatable in the disc storage portion and that the first side of the disc is exposed inside the disc window. The chucking opening is preferably formed on the bottom of the disc storage portion so as to get the disc chucked externally. The head opening is also preferably formed on the bottom of the disc storage portion so as to allow a head, which reads and/or writes a signal from/on the second side of the disc, to access the second side of the disc. The first and second shutters are preferably provided on the bottom of the disc storage portion for the purpose of exposing or covering the head opening. The rotational member is preferably provided over the first and second shutters inside the disc storage portion and is preferably interlocked with the first and second shutters in such a manner as to open or close the first and second shutters when rotates inside the disc storage portion. The disc holder preferably holds the disc thereon in such a manner as not to contact with a clamp area, which is provided on the second side of the disc, while the first and second shutters are closed.

[0035] In this particular preferred embodiment, the disc holder holds the disc in such a manner as not to contact with protruding ring provided on the second side of the disc in the vicinity clamp area. Further, when the first and second shutters are closed, the disc holder holds the disc in such a manner as not to contact with neither a clamp area nor a region which is located between the clamp area and the center hole and which is apart from the edge of the center hole by 0.1 mm or more or in such a manner as not to contact with neither a clamp area nor a region which is located between the clamp area and the signal recording area and which is apart from the edge of the clamp area by 2 mm or less.

[0036] A disc cartridge according to yet another preferred embodiment of the present invention preferably includes a cartridge body, first and second shutters, and a rotational member. The cartridge body preferably includes a disc storage portion, a chucking opening and a head opening. The disc storage portion preferably has a disc window and a bottom and preferably stores a disc, having first and second sides, therein so that the disc is rotatable in the disc storage portion and that the first side of the disc is exposed inside the disc window. The chucking opening is preferably formed on the bottom of the disc storage portion so as to get the disc chucked externally. The head opening is also preferably formed on the bottom of the disc storage portion so as to allow a head, which reads and/or writes a signal from/on the second side of the disc, to access the second side of the disc. The first and second shutters are preferably provided on the bottom of the disc storage portion for the purpose of exposing or covering the head opening. The rotational member is preferably provided over the first and second shutters inside the disc storage portion and is preferably interlocked with the first and second shutters in such a manner as to open or close the first and second shutters when rotates inside the disc storage portion. The first and second shutters preferably have first and second pairs of contact portions in two separate regions. The contact portions of each of the first and second pairs preferably contact and overlap with each other in a thickness direction. An order in which the contact portions of the first pair overlap with each other is preferably reverse to an order in which the contact portions of the second pair overlap with each other.

[0037] In one preferred embodiment of the present invention, the first and second shutters preferably further include a sidewall, which stands in the vicinity of the first pair of contact portions, and a third pair of contact portions. The third pair of contact portions preferably contacts and overlaps with each other in the thickness direction over the sidewall. One of the two contact portions of the first pair and one of the two contact portions of the third pair of the first or second shutter preferably contact with, and sandwich, the other contact portion of the first pair and the other contact portion of the third pair of the second or first shutter.

[0038] A disc cartridge according to yet another preferred embodiment of the present invention preferably includes a cartridge body, first and second shutters, and a rotational member. The cartridge body preferably includes a disc storage portion, a chucking opening and a head opening. The disc storage portion preferably has a disc window and a bottom and preferably stores a disc, having first and second sides, therein so that the disc is rotatable in the disc storage portion and that the first side of the disc is exposed inside the disc window. The chucking opening is preferably formed on the bottom of the disc storage portion so as to get the disc chucked externally. The head opening is also preferably formed on the bottom of the disc storage portion so as to allow a head, which reads and/or writes a signal from/on the second side of the disc, to access the second side of the disc. The first and second shutters are preferably provided on the bottom of the disc storage portion for the purpose of exposing or covering the head opening. The rotational member is preferably provided over the first and second shutters inside the disc storage portion and is preferably interlocked with the first and second shutters in such a manner as to open or close the first and second shutters when rotates inside the disc storage portion. The first and second shutters closed preferably contact with each other to define a hole in a region corresponding to a center hole of the disc. A contact portion of one of the first and second shutters preferably includes a convex portion around the hole, while a contact portion of the other shutter preferably includes a concave portion, which engages with the convex portion, around the hole.

[0039] A disc cartridge according to yet another preferred embodiment of the present invention preferably includes a cartridge body, first and second shutters, and a rotational member. The cartridge body preferably includes a disc storage portion, a chucking opening and a head opening. The disc storage portion preferably has a disc window and a bottom and preferably stores a disc, having first and second sides, therein so that the disc is rotatable in the disc storage portion and that the first side of the disc is exposed inside the disc window. The chucking opening is preferably formed on the bottom of the disc storage portion so as to get the disc chucked externally. The head opening is also preferably formed on the bottom of the disc storage portion so as to allow a head, which reads and/or writes a signal from/on the second side of the disc, to access the second side of the disc. The first and second shutters are preferably provided on the bottom of the disc storage portion for the purpose of exposing or covering the head opening. The rotational member is preferably provided over the first and second shutters inside the disc storage portion and is preferably interlocked with the first and second shutters in such a manner as to open or close the first and second shutters when rotates inside the disc storage portion. The first and second shutters preferably include a plurality of disc holders that contacts with an outer side surface of the disc and its surround portions and that holds the disc thereon while the first and second shutters are closed. The rotational member preferably includes a sidewall that contacts with at least one of the disc holders in such a manner as to prevent the at least one disc holder from being deformed in a radial direction of the disc while the first and second shutters are closed.

[0040] A disc cartridge according to yet another preferred embodiment of the present invention preferably includes a cartridge body, first and second shutters, and a rotational member. The cartridge body preferably includes a disc storage portion, a chucking opening and a head opening. The disc storage portion preferably has a disc window and a bottom and preferably stores a disc, having first and second sides, therein so that the disc is rotatable in the disc storage portion and that the first side of the disc is exposed inside the disc window. The chucking opening is preferably formed on the bottom of the disc storage portion so as to get the disc chucked externally. The head opening is also preferably formed on the bottom of the disc storage portion so as to allow a head, which reads and/or writes a signal from/on the second side of the disc, to access the second side of the disc. The first and second shutters are preferably provided on the bottom of the disc storage portion for the purpose of exposing or covering the head opening. The rotational member is preferably provided over the first and second shutters inside the disc storage portion and is preferably interlocked with the first and second shutters in such a manner as to open or close the first and second shutters when rotates inside the disc storage portion. The cartridge body preferably includes a rim, which is provided on the bottom of the disc storage portion so as to surround the chucking and head openings. The first and second shutters preferably include respective concave portions on their back surfaces, which are opposed to the bottom of the disc storage portion, to receive the rim.

[0041] A disc cartridge according to yet another preferred embodiment of the present invention preferably includes a cartridge body, first and second shutters, and a rotational member. The cartridge body preferably includes a disc storage portion, a chucking opening and a head opening. The disc storage portion preferably has a disc window and a bottom and preferably stores a disc, having first and second sides, therein so that the disc is rotatable in the disc storage portion and that the first side of the disc is exposed inside the disc window. The chucking opening is preferably formed on the bottom of the disc storage portion so as to get the disc chucked externally. The head opening is also preferably formed on the bottom of the disc storage portion so as to allow a head, which reads and/or writes a signal from/on the second side of the disc, to access the second side of the disc. The first and second shutters are preferably provided on the bottom of the disc storage portion for the purpose of exposing or covering the head opening. The rotational member is preferably provided over the first and second shutters inside the disc storage portion and is preferably interlocked with the first and second shutters in such a manner as to open or close the first and second shutters when rotates inside the disc storage portion. The cartridge body preferably includes engaging means that is selectively engageable with a first or second disc stopper so that each of the first and second disc stoppers is attachable to the cartridge body. The first disc stopper is preferably movable from a first position, at which the first disc stopper protrudes partially over the disc that is stored inside the disc storage portion, to a second position, at which the first disc stopper is not located over the disc, or vice versa. The second disc stopper is preferably fixed at the first position.

[0042] A disc cartridge according to yet another preferred embodiment of the present invention preferably includes a cartridge body, first and second shutters, and a rotational member. The cartridge body preferably includes a disc storage portion, a chucking opening and a head opening. The disc storage portion preferably has a disc window and a bottom and preferably stores a disc, having first and second sides, therein so that the disc is rotatable in the disc storage portion and that the first side of the disc is exposed inside the disc window. The chucking opening is preferably formed on the bottom of the disc storage portion so as to get the disc chucked externally. The head opening is also preferably formed on the bottom of the disc storage portion so as to allow a head, which reads and/or writes a signal from/on the second side of the disc, to access the second side of the disc. The first and second shutters are preferably provided on the bottom of the disc storage portion for the purpose of exposing or covering the head opening. The rotational member is preferably provided over the first and second shutters inside the disc storage portion and is preferably interlocked with the first and second shutters in such a manner as to open or close the first and second shutters when rotates inside the disc storage portion. The first and second shutters are preferably disposed so as to be sandwiched between the rotational member and the bottom of the disc storage portion. The cartridge body preferably includes a raised portion, which has a height that is approximately equal to the thickness of the first and second shutters, on the bottom of the disc storage portion.

[0043] A disc drive according to yet another preferred embodiment of the present invention is preferably loaded with the disc cartridge according to any of the preferred embodiments of the present invention described above and preferably reads and/or writes a signal from/on the disc that is stored in the disc cartridge.

[0044] A disc drive according to yet another preferred embodiment of the present invention preferably includes driving means, a head, a supporting structure, and a shutter opening/closing mechanism. The driving means preferably rotates a disc. The head preferably reads and/or writes a signal from/on the disc. The supporting structure preferably supports the disc cartridge according to any of the preferred embodiments of the present invention described above, which stores the disc therein, at a predetermined position with respect to the driving means. The shutter opening/closing mechanism preferably opens the shutter of the disc cartridge and gets the disc released from the disc holder so that the disc is rotatable inside the disc storage portion of the disc cartridge.

[0045] In one preferred embodiment of the present invention, the disc drive preferably further includes a clamper for mounting the disc onto the driving means.

[0046] In this particular preferred embodiment, the supporting structure preferably includes a positioning pin for fixing the disc cartridge at the predetermined position.

[0047] Other features, elements, processes, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the present invention with reference to the attached drawings.

BRIEF DESCRIPTION OF DRAWINGS

[0048]FIG. 1 is a perspective view illustrating an overall configuration for a disc cartridge according to a first specific preferred embodiment of the present invention.

[0049]FIG. 2 is a perspective view of the disc cartridge shown in FIG. 1 as viewed from below it.

[0050]FIG. 3 is an exploded perspective view of the disc cartridge shown in FIG. 1.

[0051]FIG. 4 is a cross-sectional view illustrating a disc holder and a surround portion of the disc cartridge shown in FIG. 1.

[0052]FIG. 5 is a cross-sectional view illustrating another disc holder and a surround portion of the disc cartridge shown in FIG. 1.

[0053]FIG. 6 is a perspective view illustrating a state of the disc cartridge shown in FIG. 1 in which its shutter is opened and positioning pins have been inserted into its positioning holes.

[0054]FIG. 7 is a cross-sectional view illustrating a disc holder and a surround portion of the disc cartridge shown in FIG. 6.

[0055]FIG. 8 is a perspective view illustrating another disc holder and a surround portion of the disc cartridge shown in FIG. 6.

[0056]FIG. 9 is a plan view illustrating an overall configuration for a disc cartridge according to a second specific preferred embodiment of the present invention.

[0057]FIG. 10 is a plan view illustrating a state of the disc cartridge shown in FIG. 9 in which the disc has been released from its disc holders.

[0058]FIG. 11 is a plan view illustrating an overall configuration for a disc cartridge according to a third specific preferred embodiment of the present invention.

[0059]FIG. 12 is a plan view illustrating a state of the disc cartridge shown in FIG. 11 in which the disc has been released from its disc holders.

[0060]FIG. 13 is a plan view illustrating an overall configuration for a disc cartridge according to a fourth specific preferred embodiment of the present invention.

[0061]FIG. 14 is a plan view illustrating a state of the disc cartridge shown in FIG. 13 in which the disc has been released from its disc holder.

[0062]FIG. 15 is a plan view illustrating an overall configuration for a disc cartridge according to a fifth specific preferred embodiment of the present invention in a state where its shutter is closed.

[0063]FIG. 16 is a cross-sectional view of a disc holder of the disc cartridge in the state shown in FIG. 15.

[0064]FIG. 17 is a plan view illustrating an overall configuration for the disc cartridge shown in FIG. 15 in a state where its shutter is opened.

[0065]FIG. 18 is a cross-sectional view of the disc holder of the disc cartridge in the state shown in FIG. 17.

[0066]FIG. 19 is a plan view illustrating an overall configuration for a disc cartridge according to a sixth specific preferred embodiment of the present invention in a state where its shutter is closed.

[0067]FIG. 20 is a plan view illustrating an overall configuration for the disc cartridge shown in FIG. 19 in a state where its shutter is opened.

[0068]FIG. 21 is a plan view illustrating an overall configuration for a disc cartridge according to a seventh specific preferred embodiment of the present invention in a state where its shutter is closed.

[0069]FIG. 22 is a plan view illustrating an overall configuration for the disc cartridge shown in FIG. 21 in a state where its shutter is opened.

[0070]FIG. 23 is a perspective view illustrating an overall configuration for a disc cartridge according to an eighth specific preferred embodiment of the present invention.

[0071]FIG. 24 is an exploded perspective view of the disc cartridge shown in FIG. 23.

[0072]FIG. 25 is a perspective view illustrating the disc cartridge shown in FIG. 23 with its upper shell and the disc removed to show a state where its shutters are closed.

[0073]FIG. 26 is a perspective view illustrating the disc cartridge shown in FIG. 23 with its upper shell and the disc removed to show a state where its shutters are opened.

[0074]FIG. 27 is a perspective view illustrating the disc cartridge shown in FIG. 23 with the disc removed to show a state where its shutters are closed.

[0075]FIG. 28 is a perspective view illustrating the disc cartridge shown in FIG. 23 with the disc removed to show a state where its shutters are opened.

[0076]FIG. 29 is a partial cross-sectional view of the disc cartridge shown in FIG. 23, which is viewed along a plane that passes the center of the disc.

[0077]FIG. 30 is a cross-sectional view illustrating a portion of the shutter of the disc cartridge shown in FIG. 23.

[0078]FIG. 31 is a partial plan view illustrating a shutter opener/closer and its surrounding portion in the disc cartridge shown in FIG. 23.

[0079]FIG. 32 is a perspective view illustrating a disc stopper of the disc cartridge shown in FIG. 23.

[0080]FIG. 33 is a front view illustrating the insertion side of the disc cartridge shown in FIG. 23.

[0081]FIG. 34 is a perspective view illustrating an overall configuration for a disc cartridge according to a ninth specific preferred embodiment of the present invention.

[0082]FIG. 35 is an exploded perspective view of the disc cartridge shown in FIG. 34.

[0083]FIG. 36 is a perspective view illustrating the disc cartridge shown in FIG. 34 with the disc removed to show a state where its shutters are closed.

[0084]FIG. 37 is a perspective view illustrating the disc cartridge shown in FIG. 34 with the disc removed to show a state where its shutters are opened.

[0085]FIG. 38 is a partial cross-sectional view of the disc cartridge shown in FIG. 34, which is viewed along a plane that passes the center of the disc to show a state where its shutters are closed.

[0086]FIG. 39 is a partial cross-sectional view of the disc cartridge shown in FIG. 34, which is viewed along a plane that passes the center of the disc to show a state where its shutters are opened.

[0087]FIG. 40 is a partial cross-sectional view illustrating a portion of the disc cartridge shown in FIG. 34 around the disc outer periphery, which is viewed along a plane passing the center of the disc to show a state where its shutters are closed.

[0088]FIG. 41 is a partial cross-sectional view illustrating a portion of the disc cartridge shown in FIG. 34 around the disc outer periphery, which is viewed along a plane passing the center of the disc to show a state where its shutters are opened.

[0089]FIG. 42 is a perspective view illustrating an overall configuration for a disc cartridge according to a tenth specific preferred embodiment of the present invention.

[0090]FIG. 43 is an exploded perspective view of the disc cartridge shown in FIG. 42.

[0091]FIG. 44 is a perspective view illustrating the disc cartridge shown in FIG. 42 with the disc removed to show a state where its shutters are closed.

[0092]FIG. 45 is a perspective view illustrating the disc cartridge shown in FIG. 42 with the disc removed to show a state where its shutters are opened.

[0093]FIG. 46 is a partial cross-sectional view of the disc cartridge shown in FIG. 42, which is viewed along a plane that passes the center of the disc to show a state where its shutters are closed.

[0094]FIG. 47 is a partial cross-sectional view of the disc cartridge shown in FIG. 42, which is viewed along a plane that passes the center of the disc to show a state where its shutters are opened.

[0095]FIG. 48 is a partial cross-sectional view illustrating a portion of the disc cartridge shown in FIG. 42 around the disc outer periphery, which is viewed along a plane passing the center of the disc to show a state where its shutters are closed.

[0096]FIG. 49 is a partial cross-sectional view illustrating a portion of the disc cartridge shown in FIG. 42 around the disc outer periphery, which is viewed along a plane passing the center of the disc to show a state where its shutters are opened.

[0097]FIG. 50 is a perspective view illustrating an overall configuration for a disc cartridge according to an eleventh specific preferred embodiment of the present invention.

[0098]FIG. 51 is an exploded perspective view of the disc cartridge shown in FIG. 50.

[0099]FIG. 52 is a perspective view illustrating the disc cartridge shown in FIG. 50 with the disc removed to show a state where its shutters are closed.

[0100]FIG. 53 is a perspective view illustrating the disc cartridge shown in FIG. 50 with the disc removed to show a state where its shutters are opened.

[0101]FIG. 54 is a partial cross-sectional view of the disc cartridge shown in FIG. 50, which is viewed along a plane that passes the center of the disc to show a state where its shutters are closed.

[0102]FIG. 55 is a partial cross-sectional view of the disc cartridge shown in FIG. 50, which is viewed along a plane that passes the center of the disc to show a state where its shutters are opened.

[0103]FIG. 56 is a cross-sectional view illustrating a portion of the shutter of the disc cartridge shown in FIG. 50.

[0104]FIG. 57 is a partial plan view illustrating a shutter opener/closer and its surrounding portion in the disc cartridge shown in FIG. 50.

[0105]FIG. 58 is a perspective view illustrating a disc cartridge according to a twelfth specific preferred embodiment of the present invention with the disc removed to show a state where its shutters are closed.

[0106]FIG. 59 is a partial cross-sectional view of the disc cartridge shown in FIG. 58, which is viewed along a plane that passes the center of the disc to show a state where its shutters are closed.

[0107]FIG. 60 is a perspective view illustrating the disc cartridge shown in FIG. 58 with the disc removed to show a state where its shutters are opened.

[0108]FIG. 61 is a partial cross-sectional view of the disc cartridge shown in FIG. 58, which is viewed along a plane that passes the center of the disc to show a state where its shutters are opened.

[0109]FIG. 62 is a perspective view illustrating a modified example of the disc cartridge shown in FIG. 58 with the disc removed to show a state where its shutters are closed.

[0110]FIG. 63 is a perspective view illustrating a modified example of the disc cartridge shown in FIG. 58 with the disc removed to show a state where its shutters are opened.

[0111]FIG. 64 is a perspective view illustrating an overall configuration for a disc cartridge according to a thirteenth specific preferred embodiment of the present invention.

[0112]FIG. 65 is an exploded perspective view of the disc cartridge shown in FIG. 64.

[0113]FIG. 66 is a schematic plan view illustrating a state of the disc cartridge shown in FIG. 64 in which its shutters are closed.

[0114]FIG. 67 is a schematic plan view illustrating a state of the disc cartridge shown in FIG. 64 in which its shutters are opened.

[0115]FIG. 68 is a plan view illustrating the details of the shutter locking mechanism of the disc cartridge shown in FIG. 64.

[0116]FIG. 69 is a cross-sectional view illustrating the details of the disc holder of the shutter in the disc cartridge shown in FIG. 64.

[0117]FIG. 70 is a cross-sectional view illustrating the shapes of a pair of contact portions between the two shutters of the disc cartridge shown in FIG. 64.

[0118]FIG. 71 is a cross-sectional view illustrating the shapes of another pair of contact portions between the two shutters of the disc cartridge shown in FIG. 64.

[0119]FIG. 72 is a perspective view illustrating an overall configuration for a disc cartridge according to a fourteenth specific preferred embodiment of the present invention.

[0120]FIG. 73 is a perspective view illustrating the shutters of the disc cartridge shown in FIG. 72.

[0121]FIG. 74 is a perspective view illustrating the disc holders and their surrounding members of the disc cartridge shown in FIG. 72 to a larger scale.

[0122]FIG. 75 is a perspective view illustrating the disc holder and its surrounding portion in the disc cartridge shown in FIG. 72 to a larger scale.

[0123]FIG. 76 is a cross-sectional view illustrating the disc holder and its surrounding members in the disc cartridge shown in FIG. 72 to a larger scale.

[0124]FIG. 77 is a schematic plan view illustrating a state of the disc cartridge shown in FIG. 72 in which its shutters are closed.

[0125]FIG. 78 is a schematic plan view illustrating a state of the disc cartridge shown in FIG. 72 in which its shutters are opened.

[0126]FIG. 79 is a cross-sectional view of the disc cartridge shown in FIG. 72 as viewed along the line B-B shown in FIG. 78.

[0127]FIG. 80 is a cross-sectional view of the disc cartridge shown in FIG. 72 as viewed along the line C-C shown in FIG. 78.

[0128]FIG. 81 is a cross-sectional view of the disc cartridge shown in FIG. 72 as viewed along the line A-A shown in FIG. 77.

[0129]FIG. 82 is a cross-sectional view illustrating a modified example of the disc supporting portion.

[0130]FIG. 83 is an exploded perspective view of a disc cartridge according to a fifteenth specific preferred embodiment of the present invention.

[0131]FIG. 84 is a schematic plan view illustrating a state of the disc cartridge shown in FIG. 83 in which its shutters are closed.

[0132]FIG. 85 is a schematic plan view illustrating a state of the disc cartridge shown in FIG. 83 in which its shutters are opened.

[0133]FIG. 86 is a cross-sectional view of the disc cartridge shown in FIG. 83 as viewed along the line D-D shown in FIG. 84.

[0134]FIG. 87 is a cross-sectional view of the disc cartridge shown in FIG. 83 as viewed along the line E-E shown in FIG. 85.

[0135]FIG. 88 is a perspective view illustrating an overall configuration for a disc cartridge according to a sixteenth specific preferred embodiment of the present invention.

[0136]FIG. 89 is an exploded perspective view of the disc cartridge shown in FIG. 88.

[0137]FIG. 90 is a schematic plan view illustrating a state of the disc cartridge shown in FIG. 88 in which its shutters are closed.

[0138]FIG. 91 is a schematic plan view illustrating a state of the disc cartridge shown in FIG. 88 in which its shutters are opened.

[0139]FIG. 92 is a schematic plan view illustrating a modified example of the disc cartridge shown in FIG. 88 in which its shutters are closed.

[0140]FIG. 93 is a schematic plan view illustrating a state of the disc cartridge shown in FIG. 92 in which its shutters are opened.

[0141]FIG. 94 is a perspective view illustrating an overall configuration for a disc cartridge according to a seventeenth specific preferred embodiment of the present invention.

[0142]FIG. 95 is an exploded perspective view of the disc cartridge shown in FIG. 94.

[0143]FIG. 96 is a schematic plan view illustrating a state of the disc cartridge shown in FIG. 94 in which its shutters are closed.

[0144]FIG. 97 is a schematic plan view illustrating a state of the disc cartridge shown in FIG. 94 in which its shutters are opened.

[0145]FIG. 98 is a perspective view illustrating an overall configuration for a disc cartridge according to an eighteenth specific preferred embodiment of the present invention.

[0146]FIG. 99 is an exploded perspective view of the disc cartridge shown in FIG. 98.

[0147]FIG. 100 is a schematic plan view illustrating a state of the disc cartridge shown in FIG. 98 in which its shutters are closed.

[0148]FIG. 101 is a schematic plan view illustrating a state of the disc cartridge shown in FIG. 98 in which its shutters are opened.

[0149]FIG. 102 is an exploded perspective view of a disc cartridge according to a nineteenth specific preferred embodiment of the present invention.

[0150]FIG. 103 is a cross-sectional view illustrating a disc holder and its surrounding members in the disc cartridge shown in FIG. 102 to a larger scale.

[0151]FIG. 104 is an exploded perspective view of a disc cartridge according to a twentieth specific preferred embodiment of the present invention.

[0152]FIG. 105 is a plan view illustrating the disc cartridge shown in FIG. 104 with its upper shell removed.

[0153]FIG. 106 is a cross-sectional view of the disc cartridge shown in FIG. 104 as viewed along the line F-F shown in FIG. 105.

[0154]FIG. 107 is a plan view illustrating the shutters and rotational member of the disc cartridge shown in FIG. 104 in a state where the shutters are closed.

[0155]FIG. 108 is a cross-sectional view of the disc cartridge shown in FIG. 104 as viewed along the line G-G shown in FIG. 107.

[0156]FIG. 109 is a plan view illustrating the shutters and rotational member of the disc cartridge shown in FIG. 104 in a state where the shutters are opened.

[0157]FIG. 110 is a cross-sectional view of the disc cartridge shown in FIG. 104 as viewed along the line H-H shown in FIG. 109.

[0158]FIG. 111 is a perspective view illustrating the shielding member of the disc cartridge shown in FIG. 104.

[0159]FIG. 112 is a cross-sectional view illustrating how the shielding member shown in FIG. 111 is supported by the upper shell.

[0160]FIG. 113 is a cross-sectional view illustrating the end of the shielding member in a state where the shutters are closed.

[0161]FIG. 114 is a cross-sectional view illustrating the center of the shielding member in a state where the shutters are closed.

[0162]FIG. 115 is a cross-sectional view illustrating the end of the shielding member in a state where the shutters are opened.

[0163]FIG. 116 is a cross-sectional view illustrating the center of the shielding member in a state where the shutters are opened.

[0164]FIG. 117 is a schematic plan view illustrating a modified example of the disc cartridge shown in FIG. 104.

[0165]FIG. 118 is a schematic plan view illustrating another modified example of the disc cartridge shown in FIG. 104.

[0166]FIG. 119 is an exploded perspective view of a disc cartridge according to a twenty-first specific preferred embodiment of the present invention.

[0167]FIG. 120 is a perspective view illustrating a removal history hole and its surrounding members in the disc cartridge shown in FIG. 119 to a larger scale.

[0168]FIG. 121 is a plan view of the disc cartridge shown in FIG. 119.

[0169]FIG. 122 is a cross-sectional view illustrating portions of the disc cartridge shown in FIG. 119 around the shaft of the disc stopper as viewed along the line J-J shown in FIG. 121.

[0170]FIG. 123 is a cross-sectional view illustrating portions of the disc cartridge shown in FIG. 119 around a latching portion of the disc stopper as viewed along the line J-J shown in FIG. 121.

[0171]FIG. 124 is a cross-sectional view illustrating portions of the disc cartridge shown in FIG. 119 as viewed along the line K-K shown in FIG. 121.

[0172]FIG. 125 is a plan view illustrating a state of the disc cartridge shown in FIG. 119 in which the disc stopper has been disengaged.

[0173]FIG. 126 is a cross-sectional view illustrating respective portions of the disc cartridge shown in FIG. 119 around the shaft of the disc stopper as viewed along the line J-J shown in FIG. 125.

[0174]FIG. 127 is a cross-sectional view illustrating respective portions of the disc cartridge shown in FIG. 119 around a latching portion of the disc stopper as viewed along the line J-J shown in FIG. 125.

[0175]FIGS. 128 and 129 are plan views schematically illustrating a modified example of the disc cartridge shown in FIG. 119.

[0176]FIGS. 130 and 131 are plan views schematically illustrating another modified example of the disc cartridge shown in FIG. 119.

[0177]FIG. 132 is a plan view illustrating a disc cartridge according to a twenty-second specific preferred embodiment of the present invention.

[0178]FIG. 133 is a cross-sectional view of the disc cartridge as viewed along the line L-L shown in FIG. 132.

[0179]FIG. 134 is a cross-sectional view illustrating a portion of the disc cartridge, as viewed along the line L-L shown in FIG. 132, to a larger scale.

[0180]FIG. 135 is a plan view schematically illustrating a portion of the disc cartridge shown in FIG. 132 to a larger scale.

[0181]FIGS. 136 and 137 are cross-sectional views illustrating another portion of the disc cartridge, as viewed along the line L-L shown in FIG. 132, to a larger scale.

[0182]FIG. 138 is a cross-sectional view illustrating a space to be provided under the disc for a disc cartridge according to a twenty-third specific preferred embodiment of the present invention.

[0183]FIG. 139 is a cross-sectional view illustrating the flexure of the disc.

[0184]FIG. 140 is a cross-sectional view illustrating another exemplary space to be provided under the disc.

[0185]FIG. 141 is a cross-sectional view illustrating yet another exemplary space to be provided under the disc.

[0186]FIG. 142 is a plan view illustrating the disc cartridge of the twenty-third preferred embodiment of the present invention.

[0187]FIG. 143 is a cross-sectional view of the disc cartridge as viewed along the line P-P shown in FIG. 142.

[0188]FIG. 144 is an exploded perspective view of the disc cartridge shown in FIG. 142.

[0189]FIG. 145 is a plan view of the disc cartridge shown in FIG. 144.

[0190]FIGS. 146A and 146B are cross-sectional views of the first and second shutters of the disc cartridge shown in FIG. 145 as viewed along the lines N-N and 0-0, respectively.

[0191]FIG. 147 is a perspective view illustrating respective portions of the first and second shutters of the disc cartridge shown in FIG. 145 to a larger scale.

[0192]FIG. 148 is a cross-sectional view of the disc cartridge as viewed along the line M-M shown in FIG. 145.

[0193]FIG. 149 is a perspective view illustrating respective portions of the first and second shutters of the disc cartridge shown in FIG. 145 to a larger scale.

[0194]FIG. 150 is a cross-sectional view illustrating another modified example of the disc cartridge shown in FIG. 145.

[0195]FIG. 151 is a perspective view illustrating main parts of a disc drive according to a twenty-fourth specific preferred embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0196] Embodiment 1

[0197] Hereinafter, a disc cartridge 301 according to a first specific preferred embodiment of the present invention will be described with reference to FIGS. 1, 2 and 3. FIG. 1 is a perspective view illustrating an overall configuration of the disc cartridge 301, including a disc 100 stored, as viewed from above the cartridge 301. FIG. 2 is a perspective view of the disc cartridge 301 as viewed from below the cartridge 301. FIG. 3 is an exploded perspective view illustrating respective parts of the disc cartridge 301.

[0198] The disc 100 includes first and second sides. The first side of the disc 100, on which its label, for example, is normally printed, is illustrated in FIG. 1, while the second side thereof, i.e., the signal recording side 100A, is illustrated as the backside in FIG. 3.

[0199] As shown in FIG. 1, the disc cartridge 301 includes a lower shell 11, an upper shell 12, disc holders 13, 14 and a shutter 21.

[0200] As shown in FIG. 3, the lower shell 11 includes a chucking opening 11 c and a head opening 11 h. The chucking opening 11 c allows a chucking member (e.g., a spindle motor for rotating the disc 100) to enter the disc cartridge 301 externally. The head opening 11 h allows a head, which reads and/or writes a signal from/on the signal recording side 100A of the disc 100, to enter the disc cartridge 301 and access a target location on the disc 100. The lower shell 11 also includes two positioning holes 11 w, which engage with cartridge positioning pins 210 of a disc drive (not shown), thereby fixing the disc cartridge 301 in its predetermined position inside the disc drive. The lower shell 11 faces the signal recording side 100A of the disc 100.

[0201] The upper shell 12 includes a circular disc window 12 w, through which the disc 100 can be introduced and removed into/from the disc cartridge 301 and which expands over the entire projection area of the disc 100 to expose the upper side of the disc 100. The upper and lower shells 12 and 11 are adhered or welded together at their outer periphery, thereby forming a cartridge body 10.

[0202] A disc storage portion 10 d for storing the disc 100 therein (see FIG. 1) is defined by an inner lower surface 11 u and an inner side surface 12 i of the cartridge body 10. The inner lower surface 11 u is opposed to the signal recording side 100A of the disc 100, while the inner side surface 12 i has a substantially cylindrical shape and defines the disc window 12 w inside. That is to say, the inner lower surface 11 u is the bottom of the disc storage portion 10 d. The inner lower surface 11 u is covered with a protective layer 11 p for the purpose of preventing the signal recording side 100A of the disc 100 from getting scratched or attracting dust.

[0203] The protective layer 11 p may be appropriately selected from the group consisting of anti-scratching nonwoven fabric, dustproof nonwoven fabric, anti-scratching coating and dustproof coating. In this preferred embodiment, a sheet of a dustproof nonwoven fabric is adhered or ultrasonic welded as the protective layer 11 p to the inner lower surface ilu.

[0204] In the disc storage portion 10 d, a gap, which is wide enough to allow the disc 100 to rotate freely, is provided between the inner side surface 12 i and the outer periphery of the disc 100. Also, the top of the disc storage portion 10 d is the disc window 12 w so that the disc 100 stored in the disc storage portion 10 d has one of its sides exposed inside the disc window 12 w.

[0205] As shown in FIG. 3, the disc cartridge 301 includes two disc holders 13 of the same shape. Each of the disc holders 13 includes a pair of elastic portions 13 d and a hole 13 w that runs obliquely through the disc holder 13. When the elastic portions 13 d of the disc holders 13 are sandwiched between the upper and lower shells 12 and 11, an elastic force is applied to the respective inner ends of the disc holders 13 in the direction indicated by the arrows 13B in FIG. 3. As a result, the disc 100 is pressed against the inner lower surface 11 u. Also, these two disc holders 13 are disposed so that the holes 13 w thereof are located substantially over the positioning holes 11 w.

[0206] The other disc holder 14 includes a shaft 14 s and two elastic portions 14 d. The disc holder 14 is secured to the cartridge body 10 so as to rotate on the shaft 14 s. When the elastic portions 14 d of the disc holder 14 are sandwiched between the upper and lower shells 12 and 11, an elastic force is applied to the respective inner ends of the disc holder 14 in the direction indicated by the arrow 14B in FIG. 1. As a result, the disc 100 is pressed against the inner lower surface 11 u.

[0207] The shutter 21 is externally fitted with the lower shell 11 so as to face the signal recording side 100A of the disc 100. As shown in FIGS. 1 and 2, when the shutter 21 is moved horizontally in the direction indicated by the arrow 21A or 21B, the chucking opening 11 c and the head opening 11 h are exposed or covered. A shutter spring 31 is extended between the shutter 21 and the cartridge body 10 to apply an elastic force to the shutter 21 in such a direction as to close the shutter 21.

[0208] As shown in FIG. 2, a label plane or concave portion 10 f, on which the user can note down the contents of the disc 100 stored, is provided on the bottom of the cartridge body 10 (i.e., the lower shell 11). As also shown in FIG. 2, a pair of concave portions 10 c, provided on the right- and left-hand sides of the cartridge body 10, may be used as either pull-in notches or positioning recesses when the disc cartridge 301 is pulled in and loaded into a disc drive or when the disc cartridge 301 is stored in a changer. Another concave portion 10 g is provided near one of the concave portions 10 c. This concave portion 10 g has such a shape as to prevent the user from inserting this disc cartridge 301 in a wrong direction. That is to say, this concave portion 10 g is just fitted with a convex portion, provided for the disc drive, only when the disc cartridge 301 is inserted in the correct direction. Suppose the user tries to insert the disc cartridge 301 into the disc drive upside down or the wrong way round. In that case, these concave and convex portions are never fitted with each other, thereby preventing the user from inserting this disc cartridge 301 in the wrong way.

[0209] Next, it will be described in further detail with reference to FIGS. 4 and 5 how the disc holders 13 and 14 hold the disc 100 thereon. FIG. 4 is a cross-sectional view of the disc holder 13 in a state where the disc 100 has been mounted thereon as shown in FIGS. 1 through 3, while FIG. 5 is a cross-sectional view of the disc holder 14 in the state where the disc 100 has been mounted thereon. FIGS. 3 and 4 are both taken in a disc radial direction.

[0210] As shown in FIGS. 4 and 5, the disc holders 13 and 14 include slopes 13′ and 14′, which are expanded over a portion of the projection area of the disc 100 (i.e., over the outer periphery of the disc 100), at the respective inner ends thereof. As described above, an elastic force is applied from the elastic portions 13 d or 14 d to the disc holder 13 or 14 in the direction indicated by the arrow 13B or 14B. In that situation, the slope 13′ or 14′ contacts with the outer edge 100 c of the disc 100, thereby gripping the disc 100 thereon and pressing the disc 100 in a thickness direction loot thereof. As a result, the signal recording side 100A of the disc 100 is brought into tight contact with the sheet 11 p. In this manner, the disc 100 is fixed inside the cartridge body 10. In this state, the outer periphery of the signal recording side 100A of the disc 100 keeps a close contact with the sheet 11 p. Thus, no dust will be deposited on the signal recording side 100A.

[0211] Next, it will be described in detail with reference to FIGS. 6, 7 and 8 how the disc 100 is released from the disc holders 13 and 14.

[0212]FIG. 6 is a perspective view illustrating the lower shell 11 of the disc cartridge 301 with the upper shell 12 and the disc 100 removed therefrom. As shown in FIG. 6, the shutter 21 has its L-shaped portion 21 s pressed by a shutter opening mechanism (not shown) of the disc drive in the direction indicated by the arrow 21A. As a result, the chucking opening and the head opening 11 h are now exposed. Also, the cartridge positioning pins 210 of the disc drive are engaged with the positioning holes 11 w of the cartridge body 10.

[0213]FIG. 7 is a cross-sectional view of the disc holder 13 in the state shown in FIG. 6 and is taken in a disc radial direction. FIG. 8 is a perspective view illustrating the disc holder 14 and the shutter 21 in the state shown in FIG. 6 to a larger scale.

[0214] As shown in FIG. 7, when the cartridge positioning pin 210 of the disc drive is inserted into the positioning hole 11 w of the lower shell 11, the cartridge positioning pin 210 engages with the obliquely running hole 13 w of the disc holder 13. As a result, the disc holder 13 is lifted in the direction indicated by the arrow 13A, and the disc 100 is released from the grip of the slope 13′ and is now freely rotatable. At this point in time, the rim 13 e at the end of the disc holder 13 still hangs over a portion of the projection area of the disc 100 (i.e., the outer periphery thereof). Accordingly, even if the disc 100 is released in the disc cartridge 301 that has been loaded into a vertically mounted disc drive, the disc 100 will not drop down from the disc cartridge 301.

[0215] On the other hand, when the shutter 21 is opened, a guide rib 21 x provided on the shutter 21 enters a concave portion 14 w of the disc holder 14, thereby raising the bottom of the concave portion 14 w as shown in FIG. 8. As a result, the disc holder 14 is lifted to the direction indicated by the arrow 14A and the disc 100 is released from the grip of the slope 14′ and becomes freely rotatable. At this point in time, the rim 14 e at the end of the disc holder 14 still hangs over a portion of the projection area of the disc 100 (i.e., the outer periphery thereof). Accordingly, even if the disc 100 is released in the disc cartridge 301 that has been loaded into a vertically mounted disc drive, the disc 100 will not drop down from the disc cartridge 301.

[0216] Also, to remove the disc 100 intentionally, the user must release the disc 100 from the three disc holders 13 and 14 at the same time. Accordingly, it is possible to prevent the user from removing the disc 100 accidentally.

[0217] In this preferred embodiment, the end 21 r of the shutter 21, which is opposed to the signal recording side 100A of the disc 100 when the shutter 21 is closed, may be provided with a brush or a dust cleaner as shown in FIG. 2 so that dust is removed from the signal recording side 100A of the disc 100 every time the shutter 21 is opened and closed. Optionally, the disc cartridge 301 may also include a locking mechanism for locking the disc holders 13 and 14 onto the cartridge body 10 when the disc 100 is mounted thereon.

[0218] Embodiment 2

[0219] Hereinafter, a disc cartridge 302 according to a second specific preferred embodiment of the present invention will be described with reference to FIGS. 9 and 10. Specifically, FIG. 9 is plan view illustrating an overall configuration for the disc cartridge 302 in which the disc 100 is held by disc holders. FIG. 10 is a plan view illustrating an overall configuration for the disc cartridge 302 in which the disc 100 has been released from the disc holders. In FIGS. 9 and 10, each member having substantially the same function as the counterpart of the first preferred embodiment described above is identified by the same reference numeral and the description thereof will be omitted herein.

[0220] The disc cartridge 302 of the second preferred embodiment is different from the disc cartridge 301 of the first preferred embodiment in the function and structure of the disc holders. Specifically, the disc cartridge 302 of the second preferred embodiments includes two pairs of disc holders 15 and 16, which slide in the direction indicated by the arrow 15A or 15B, as shown in FIG. 9.

[0221] Each of the disc holders 15 includes an elastic portion 15 d, which applies an elastic force to the disc holder 15 in the direction indicated by the arrow 15B. Just like the disc holders 13 and 14 of the first preferred embodiment, a slope 15′ provided at the end of each disc holder 15 presses and fixes the disc 100 against the cartridge body 10.

[0222] Each of the disc holders 16 includes a shaft 16 c. That is to say, the disc holder 16 is provided for the cartridge body 10 so as to rotate on its shaft 16 c. Just like the disc holders 13 and 14 of the first preferred embodiment, a slope 16′ provided at the end of each disc holder 16 presses and fixes the disc 100 against the cartridge body 10. Each of the disc holders 15 further includes a coupling pin 15 p, which is engaged and interlocked with a groove 16 g of its associated disc holder 16.

[0223] When the two cartridge positioning pins 210 of the disc drive are engaged with the positioning holes 11 w of the cartridge body 10, respective protrusions 15 s of the disc holders 15 are pushed and lifted by the positioning pins 210 as shown in FIG. 10. As a result, the disc holders 15 are moved in the direction indicated by the arrow 15A and the disc 100 is released from the grip of the slopes 15′. In the meantime, as the disc holders 15 are moved in the direction 15A, the disc holders 16 are rotated to the direction indicated by the arrow 16A. Consequently, the disc 100 is also released from the grip of the slopes 16′.

[0224] Embodiment 3

[0225] Hereinafter, a disc cartridge 303 according to a third specific preferred embodiment of the present invention will be described with reference to FIGS. 11 and 12. Specifically, FIG. 11 is plan view illustrating an overall configuration for the disc cartridge 303 in which the disc 100 is held by disc holders. FIG. 12 is a plan view illustrating an overall configuration for the disc cartridge 303 in which the disc 100 has been released from the disc holders. In FIGS. 11 and 12, each member having substantially the same function as the counterpart of the first preferred embodiment described above is identified by the same reference numeral and the description thereof will be omitted herein.

[0226] The disc cartridge 303 of the third preferred embodiment is different from the disc cartridge 301 of the first preferred embodiment in the function and structure of the disc holders. Specifically, the disc cartridge 303 of the third preferred embodiments includes two pairs of disc holders 17 and 18, to which an elastic force is applied in the directions indicated by the arrows 17B and 18B, respectively, as shown in FIG. 11. These disc holders 17 and 18 have been molded together with the cartridge body 10 so as to form integral parts of the cartridge body 10.

[0227] Each of the disc holders 17 includes an elastic portion 17 d, which applies an elastic force to the disc holder 17 in the direction indicated by the arrow 17B. Just like the disc holders 13 and 14 of the first preferred embodiment, a slope 17′ provided at the end of each disc holder 17 presses and fixes the disc 100 against the cartridge body 10.

[0228] Each of the disc holders 18 also includes an elastic portion 18 d, which applies an elastic force to the disc holder 18 in the direction indicated by the arrow 18B. A slope 18′ provided at the end of each disc holder 18 also presses and fixes the disc 100 against the cartridge body 10.

[0229] When this disc cartridge 303 is inserted into a disc drive 200, a pair of disc releasing pins 217, provided for the disc drive 200, presses protrusions 17 s of the disc holders 17. As a result, the disc 100 is released from the disc holders 17 as shown in FIG. 12. At the same time, another pair of disc releasing pins 218, also provided for the disc drive 200, contacts with the side surfaces 18 s of the disc holders 18. Consequently, the disc 100 is also released from the disc holders 18 as shown in FIG. 12.

[0230] Embodiment 4

[0231] Hereinafter, a disc cartridge 304 according to a fourth specific preferred embodiment of the present invention will be described with reference to FIGS. 13 and 14. Specifically, FIG. 13 is plan view illustrating an overall configuration for the disc cartridge 304 in which the disc 100 is held by a disc holder. FIG. 14 is a plan view illustrating an overall configuration for the disc cartridge 304 in which the disc 100 has been released from the disc holder. In FIGS. 13 and 14, each member having substantially the same function as the counterpart of the first preferred embodiment described above is identified by the same reference numeral and the description thereof will be omitted herein.

[0232] The disc cartridge 304 of the fourth preferred embodiment is different from the disc cartridge 301 of the first preferred embodiment in the function and structure of the disc holder. Specifically, the disc cartridge 304 includes a ringlike disc holder 19.

[0233] As shown in FIG. 13, the disc holder 19 is a ring-like elastic member, which is made of rubber, for example, and can change its shape freely. When no force is externally applied hereto, the disc holder 19 has an ellipsoidal planar shape. However, by applying an external force thereto, the disc holder 19 may be deformed into a substantially completely round shape. In that case, the inside diameter of the disc holder 19 is greater than the diameter of the disc 100.

[0234] As shown in FIG. 13, the ellipsoidal disc holder 19 is in contact with the disc 100 at multiple points, thereby fixing the disc 100 onto the cartridge body 10. However, when this disc cartridge 304 is inserted into a disc drive 200, convex portions 219, provided for the disc drive 200, press the major axis portion of the ellipsoidal disc holder 19, thereby deforming the disc holder 19 as shown in FIG. 14. As a result, the disc holder 19 is deformed into an approximately completely round shape and is no longer in contact with the disc 100. That is to say, the disc 100 is released from the disc holder 19.

[0235] To release the disc 100 from the disc holder 19, the force that deforms the disc holder 19 may also be applied from the convex portion of the disc drive 200, which engages with the concave portion 10 g (see FIG. 2) provided for preventing the user from inserting the disc cartridge in the wrong direction, to the disc holder 19. Alternatively, that force may also be applied from a pair of convex portions of the disc drive 200, which engages with the concave portions 10 c (see FIG. 2) provided on the right- and left-hand sides of the disc cartridge 304 for pulling in the disc cartridge 304, to the disc holder 19.

[0236] Embodiment 5

[0237] Hereinafter, a disc cartridge 305 according to a fifth specific preferred embodiment of the present invention will be described with reference to FIGS. 15 through 18. FIGS. 15 and 17 are plan views illustrating the structure of the disc cartridge 305 of the fifth preferred embodiment from which the upper shell has been removed. Specifically, FIG. 15 illustrates a state where the shutter 21 covers the openings 11 h and 11 c, while FIG. 17 illustrates a state where the shutter 21 exposes the openings 11 h and 11 c. FIGS. 16 and 18 illustrate states of a disc holder 43 when the shutter 21 is closed and when the shutter 21 is opened, respectively.

[0238] In FIGS. 15 through 18, each member having substantially the same function as the counterpart of the first preferred embodiment described above is identified by the same reference numeral.

[0239] The disc cartridge 305 of the fifth preferred embodiment is characterized in that the disc holding and releasing operations and the opening and closing operations are synchronously performed by disc holders 43 and the shutter 21, respectively, by way of a disc holder/shutter interlocking member 44.

[0240] The disc holder/shutter interlocking member 44 is provided over the inner lower surface 11 u so as to rotate and slide around the chucking opening 11 c of the lower shell 11 as indicated by the arrow 44A in FIGS. 15 and 17. The disc holder/shutter interlocking member 44 has a fan shape, or in the shape of a partially notched ring that has an inside diameter equal to the diameter of the chucking opening 11 c.

[0241] The disc holder/shutter interlocking member 44 includes a pin 47 that extends toward the lower shell 11 (i.e., in the direction going into the paper of FIGS. 15 and 17). The lower shell 11 and the shutter 21 are respectively provided with guide grooves 11 m and 21 m that both engage with the pin 47. Also, multiple protrusions 45, which extend outward and upward (i.e., in the direction coming out of the paper of FIGS. 15 and 17), are provided on the outer periphery of the disc holder/shutter interlocking member 44. Furthermore, the upper surface of the disc holder/shutter interlocking member 44 is covered with a nonwoven fabric or a coating to prevent the signal recording side 100A of the disc 100 from getting scratched or attracting dust.

[0242] A number of disc holders 43 are disposed at predetermined intervals on the inner lower surface 11 u so as to hold the outer edge of the disc 100 thereon when the disc 100 is stored in the disc cartridge 305. In the preferred embodiment shown in FIGS. 15 and 17, three disc holders 43 are provided. Alternatively, two, four or more disc holders 43 may also be provided. In any case, each of those disc holders 43 is secured to the lower shell 11 so as to rotate on the shaft 43A thereof.

[0243] As shown in FIG. 16, each of the disc holders 43 is located at such a position so as to partially overlap with the outer periphery of the disc holder/shutter interlocking member 44. Also, an elastic portion (not shown in FIG. 16) such as the elastic portion 14 d shown in FIG. 5, for example, applies an elastic force to each disc holder 43 downward (i.e., toward the lower shell 11). Accordingly, while contacting with the outer edge of the disc 100, the slope 43′ of the disc holder 43 not only presses the disc 100 in the direction indicated by the arrow 43B in FIG. 16 so that the disc 100 is brought into contact with the disc holder/shutter interlocking member 44 but also holds the disc 100 thereon.

[0244] As shown in FIG. 15, when the disc cartridge 305 including the disc (not shown) is inserted into a disc drive 200 in the direction indicated by the arrow 1A, a shutter opener/closer (not shown), provided for the disc drive 200, moves the shutter 21 in the direction indicated by the arrow 21A, thereby opening the shutter 21. When the shutter 21 starts to move in the direction 21A, a force is also applied in the direction 21A to the pin 47 of the disc holder/shutter interlocking member 44 that is engaged with the guide groove 21 m of the shutter 21. As a result, the pin 47 is moved along the guide groove 11 m of the lower shell 11, and the disc holder/shutter interlocking member 44 starts to rotate to the direction indicated by the arrow 44A around the chucking opening 11 c. The guide groove 11 m preferably extends approximately in the direction in which the shutter 21 is moved so that the disc holder/shutter interlocking member 44 moves along with the shutter 21.

[0245] When the shutter 21 is completely open, the protrusions 45 on the outer periphery of the disc holder/shutter interlocking member 44 are located under the disc holders 43 as shown in FIG. 17. Then, as shown in FIG. 18, the disc holders 43 are pushed up by the protrusions 45 and the slopes 43′ of the disc holders 43 separate themselves from the outer edge of the disc 100. As a result, the force that has been vertically applied to the disc 100 in the direction indicated by the arrow 43B is removed from the disc 100 and the disc 100 is now freely rotatable. At this point in time, the rim 43 e at the end of the disc holder 43 still hangs over a portion of the projection area of the disc 100 (i.e., the outer periphery thereof). Accordingly, even if the disc 100 is released in the disc cartridge 305 that has been loaded into a vertically mounted disc drive, the disc 100 will not drop down from the disc cartridge 305.

[0246] In the disc cartridge 305 of the fifth preferred embodiment, the disc can be released even if the disc cartridge 305 is not inserted into the disc drive 200. Accordingly, if the shutter 21 is opened manually, the disc holders 43 will release the disc 100 synchronously with the movement of the shutter 21. Thus, the user can remove an unwanted disc from the cartridge 305 and insert a new disc thereto any time he or she likes.

[0247] Embodiment 6

[0248] Hereinafter, a disc cartridge 306 according to a sixth specific preferred embodiment of the present invention will be described with reference to FIGS. 19 and 20. FIGS. 19 and 20 are plan views illustrating the structure of the disc cartridge 306 of the sixth preferred embodiment from which the upper shell has been removed. Specifically, FIG. 19 illustrates a state where the shutter covers the head opening 11 h, while FIG. 20 illustrates a state where the shutter exposes the opening 11 h. In FIGS. 19 and 20, each member having substantially the same function as the counterpart of the first or fifth preferred embodiment described above is identified by the same reference numeral.

[0249] The disc cartridge 306 of the sixth preferred embodiment is characterized in that the shutter 46 thereof performs the functions of the disc holder/shutter interlocking member 44 and the shutter 21 of the disc cartridge 305 of the fifth preferred embodiment. The shutter 46 is provided over the inner lower surface 11 u so as to rotate and slide around the chucking opening 11 c of the lower shell 11 as indicated by the arrow 46B in FIGS. 19 and 20. The shutter 46 has a fan shape, or in the shape of a partially notched ring that has an inside diameter equal to the diameter of the chucking opening 11 c.

[0250] The shutter 46 includes a pin 46 p that extends toward the lower shell 11 (i.e., in the direction going into the paper of FIGS. 19 and 20). The lower shell 11 is provided with a guide groove 11 m that engages with the pin 46 p. When the pin 46 p is located at one end of the guide groove 11 m, the head opening 11 h is closed up by the shutter 46. And when the pin 46 p is located at the other end of the guide groove 11 m, the head opening 11 h is exposed by the shutter 46. The guide groove 11 m is provided along a portion of an arc that is concentric with the chuck opening 11 c. The guide groove 11 m preferably extends approximately in the direction 1A in which the disc cartridge 306 is inserted into a disc drive 200 so that the shutter 46 is opened as the disc cartridge 306 is inserted into the disc drive 200.

[0251] Multiple protrusions 46 c, which extend outward and upward (i.e., in the direction coming out of the paper of FIGS. 19 and 20), are provided on the outer periphery of the shutter 46. Furthermore, the upper surface of the shutter 46 is covered with a nonwoven fabric or a coating to prevent the signal recording side 100A of the disc 100 from getting scratched or attracting dust.

[0252] A number of disc holders 43, having a structure similar to that of the disc holders of the fifth preferred embodiment, are disposed at predetermined intervals on the inner lower surface 11 u. The disc holders 43 and the protrusions 46 c of the shutter 46 together hold or release the disc synchronously with the movement of the shutter 46 as already described for the fifth preferred embodiment.

[0253] When the disc cartridge 306 of the sixth preferred embodiment is inserted into the disc drive 200 in the direction indicated by the arrow 1A in FIG. 19, the pin 46 p of the shutter 46 will soon contact with a contact member 201 provided for the disc drive 200. And when the disc cartridge 306 is inserted deeper into the disc drive 200, the pin 46 p is pressed by the contact member 201 to start to move along the guide groove 11 m. Then, the shutter 46 starts to rotate around the chucking opening 11 c of the lower shell 11 to the direction indicated by the arrow 46B in FIG. 19. As the shutter 46 rotates to that direction, the head opening 11 h is opened little by little.

[0254] As shown in FIG. 20, when the disc cartridge 306 has been fully inserted into the disc drive 200, the pin 46 p will reach the other end of the guide groove 11 m. As a result, the head opening 11 h is completely exposed. At this point in time, as already described for the fifth preferred embodiment, the protrusions 46 c on the outer periphery of the shutter 46 are located under the disc holders 43 as shown in FIG. 20. Then, the disc holders 43 are pushed up by the protrusions 46 c toward the upper shell 12 (i.e., in the direction coming out of the paper of FIG. 20). As a result, the disc 100 that has been held by the disc holders 43 is released and now freely rotatable.

[0255] The disc cartridge 306 of the sixth preferred embodiment needs no disc holder/shutter interlocking member. Thus, compared to the disc cartridge 305 of the fifth preferred embodiment, the disc cartridge 306 can be thinner. Also, if the pin 46 p is moved manually along the guide groove 11 m, the shutter 46 can be opened and the disc can be released and removed from the disc holders 43.

[0256] In the sixth preferred embodiment described above, the shutter 46 is rotated clockwise as viewed from over the upper shell of the cartridge 306. However, the shutter 406 may also be rotated counterclockwise if the guide groove 11 m is formed at a different position.

[0257] Embodiment 7

[0258] Hereinafter, a disc cartridge 307 according to a seventh specific preferred embodiment of the present invention will be described with reference to FIGS. 21 and 22. FIGS. 21 and 22 are plan views illustrating the structure of the disc cartridge 307 of the seventh preferred embodiment from which the upper shell has been removed. Specifically, FIG. 21 illustrates a state where the shutter covers the head opening 11 h, while FIG. 22 illustrates a state where the shutter exposes the head opening 11 h. In FIGS. 21 and 22, each member having substantially the same function as the counterpart of the third or sixth preferred embodiment described above is identified by the same reference numeral.

[0259] The disc cartridge 307 of the seventh preferred embodiment is different from the disc cartridge 306 of the sixth preferred embodiment in the structure of the disc holders. Specifically, as shown in FIGS. 21 and 22, the disc cartridge 307 includes a plurality of disc holders 17. Just like the disc holders of the third preferred embodiment described above, each of these disc holders 17 also includes an elastic portion 17 d. While the shutter 46 is going to be closed, the elastic portions 17 d apply an elastic force to the disc 100 mounted, thereby holding and pressing the disc 100 toward the center thereof as indicated by the arrows 17R in FIG. 21. In this preferred embodiment, the disc holders 17 form integral parts of the lower shell 11. Alternatively, the disc holders 17 may also be formed separately from the lower shell 11.

[0260] When taken in the disc radial direction, each of these disc holders 17 also has a slope that expands over a portion of the projection area of the disc (i.e., the outer periphery of the disc 100) just like the disc holder 43 shown in FIG. 18. Accordingly, if the disc 100 gets held by the disc holders 17 so as to have its outer edge contact with the respective slopes of the disc holders 17, then the disc 100 is pressed against the shutter 46.

[0261] The shutter 46 includes a plurality of protrusions 46 c on the outer periphery thereof. In this preferred embodiment, the protrusions 46 c protrude outward. Also, the protrusions 46 c are located at such positions on the outer periphery of the shutter 46 as to contact with the elastic portions 17 d of the disc holders 17 when the shutter 46 is opened as shown in FIG. 22.

[0262] As shown in FIG. 22, when the shutter 46 is opened, the protrusions 46 c dominate the inwardly applied elastic force of the elastic portions 17 d, thereby pushing the elastic portions 17 d outward as indicated by the arrows 17 s. As a result, the disc 100 is released. However, each of the disc holders 17 also includes a rim 17 e at the end thereof. Even after the disc 100 has been released, the rim 17 e still hangs over a portion of the projection area of the disc 100. Accordingly, even if the disc 100 is released in the disc cartridge 307 that has been loaded into a vertically mounted disc drive 200, the disc 100 will not drop down from the disc cartridge 307.

[0263] The disc cartridge 307 of the seventh preferred embodiment achieves all the effects of the sixth preferred embodiment described above. In addition, according to this seventh preferred embodiment, the disc holders 17 may form integral parts of the lower shell 11. Then, the disc cartridge can have a simplified structure and can be formed at a low manufacturing cost.

[0264] Embodiment 8

[0265] Hereinafter, a disc cartridge 308 according to an eighth specific preferred embodiment of the present invention will be described with reference to the accompanying drawings.

[0266] First, the structure of the disc cartridge 308 will be outlined with reference to FIGS. 23 and 24. As in the first preferred embodiment described above, the disc 100 shown in FIGS. 23 and 24 also includes first and second sides. The first side of the disc, on which its label, for example, is normally printed, is illustrated in FIG. 23, while the second side thereof, i.e., the signal recording side 100A, is illustrated as the backside in FIG. 24.

[0267] As shown in FIGS. 23 and 24, the disc cartridge 308 includes a lower shell 11, an upper shell 12, a pair of shutters 21 and 22 and disc stoppers 23.

[0268] As shown in FIG. 24, the lower shell 11 includes a chucking opening 11 c and a head opening 11 h. The chucking opening 11 c allows a chucking member (e.g., a spindle motor for rotating the disc 100) to enter the disc cartridge 308 externally. The head opening 11 h allows a head, which reads and/or writes a signal from/on the signal recording side 100A of the disc 100, to enter the disc cartridge 308 and access a target location on the disc 100. The lower shell 11 faces the signal recording side 100A of the disc 100. Also, the head opening 11 h reaches a side surface of the lower shell 11.

[0269] The upper shell 12 includes a circular disc window 12 w, through which the disc 100 can be introduced and removed into/from the disc cartridge 308 and which expands over the entire projection area of the disc 100 to expose the upper side of the disc 100. The upper and lower shells 12 and 11 are adhered or welded together at their outer periphery, thereby forming a cartridge body 10.

[0270] A disc storage portion 10 d for storing the disc 100 therein is defined by an inner lower surface 11 u and an inner side surface 12 i of the cartridge body 10. The inner lower surface 11 u is opposed to the signal recording side 100A of the disc 100, while the inner side surface 12 i has a substantially cylindrical shape and defines the disc window 12 w inside. That is to say, the inner lower surface 11 u is the bottom of the disc storage portion 10 d.

[0271] In the disc storage portion 10 d, a gap, which is wide enough to allow the disc 100 to rotate freely, is provided between the inner side surface 12 i and the outer periphery of the disc 100. Also, the inner side surface 12 i is so high that the entire of the disc 100 is stored within the disc storage portion 10 d while the disc 100 is rotated. The top of the disc storage portion 10 d is the disc window 12 w so that the disc 100 stored in the disc storage portion 10 d has one of its sides exposed inside the disc window 12 w.

[0272] Two removable disc stoppers 23 are provided for the upper shell 12 so as to partially protrude into the disc window 12 w as shown in FIGS. 23 and 24. A third disc stopper 12 s is further provided for the upper shell 12 so as to protrude into the disc window 12 w. But the third disc stopper 12 s forms an integral part of the upper shell 12. These three disc stoppers 23 and 12 s are arranged substantially at regular intervals around the circumference of the disc window 12 w for the purpose of preventing the disc 100 from dropping down from the disc window 12 w during the time the shutters 21 and 22 are opened and during the time the shutters 21 and 22 are closed. These disc stoppers 23 and 12 s are effective particularly when this disc cartridge 308 is loaded into a vertically mounted disc drive.

[0273] The shutters 21 and 22 are disposed between the signal recording side 100A of the disc 100 and the inner lower surface 11 u of the cartridge body 10. The shutters 21 and 22 include shaft holes 21 u and 22 u, respectively. These shaft holes 21 u and 22 u are engaged in a freely rotatable state with shafts 11 s, which are located outside of the disc storage portion 10 d of the cartridge body 10 and on a deep side of the cartridge body 10 opposite to the head opening 11 h thereof. Thus, the shutters 21 and 22 rotate on the shafts 11 s in such a manner as to cover or expose the chucking and head openings 11 c and 11 h.

[0274] A cam 21 c and a follower 22 c are provided near the shaft holes 21 u and 22 u of the shutters 21 and 22, respectively. The cam 21 c and the follower 22 c have mutually engaging shapes and together make up an interlocking mechanism 20 c for opening and closing the shutters 21 and 22 while interlocking them with each other.

[0275] The respective upper surfaces of the shutters 21 and 22, which are opposed to the signal recording side 100A of the disc 100, are covered with protective layers 21 p and 22 p for the purpose of preventing the signal recording side 100A of the disc 100 from getting scratched or attracting dust.

[0276] The protective layers 21 p and 22 p may be appropriately selected from the group consisting of anti-scratching nonwoven fabric, dustproof nonwoven fabric, anti-scratching coating and dustproof coating. In this preferred embodiment, sheets of a dustproof nonwoven fabric are adhered or ultrasonic welded as the protective layers 21 p and 22 p to the shutters 21 and 22, respectively.

[0277] Shutter springs 31 and 32 are provided outside of the disc storage portion 10 d for the shutters 21 and 22, respectively. These springs 31 and 32 apply an elastic force to the shutters 21 and 22 in such a direction as to close the shutters 21 and 22. Optionally, an elastic force may also be applied from any other type of elastic members to the shutters 21 and 22 in that direction.

[0278] In the disc cartridge 308 shown in FIG. 24, the shutters 21 and 22 each include two disc holders 21 a, 21 b and 22 a, 22 b at both ends thereof. Each of these disc holders 21 a, 21 b, 22 a and 22 b has a downwardly tapered cross-sectional shape (or slope) to grip the outer edge of the disc 100 while the shutters 21 and 22 are closed. The structure and operation of the disc holders 21 a, 21 b, 22 a and 22 b will be described in further detail later.

[0279] As shown in FIG. 23, the upper surface of the cartridge body 10 (or the upper shell 12) has a label plane 10 f, on which the user can note down the contents of the disc 100 stored, and embossed arrow marks (or concave portions) 10 a that indicate the direction (the arrow 1A) in which this disc cartridge 308 should be inserted into a disc drive. The cartridge body 10 further includes two concave portions 10 c on two of its side surfaces that are parallel to the direction 1A in which the disc cartridge 308 is inserted. These concave portions 10 c may be used as either pull-in notches or positioning recesses when the disc cartridge 308 is pulled in and loaded into a disc drive or when the disc cartridge 308 is stored in a disc changer.

[0280]FIG. 25 is a perspective view illustrating the disc cartridge 308 with the upper shell 12 and the disc 100 removed to show a state where the shutters 21 and 22 cover the chucking and head openings 11 c and 11 h. In FIG. 25, the disc holders 21 a, 21 b, 22 a and 22 b of the shutters 21 and 22 are located at such positions as to grip the outer edge of the disc 100 (not shown in FIG. 25).

[0281]FIG. 26 is a perspective view illustrating the disc cartridge 308 with the upper shell 12 and the disc 100 removed to show a state where the shutters 21 and 22 expose the chucking and head openings 11 c and 11 h. As a result of the rotation of the shutters 21 and 22 on their shaft holes 21 u and 22 u, respectively, the chucking and head openings 11 c and 11 h are now exposed. Also, as the shutters 21 and 22 have rotated, the disc holders 21 a, 21 b, 22 a and 22 b have also rotated on the shaft holes 21 u and 22 u. Consequently, the disc holders 21 a, 21 b, 22 a and 22 b are now separated from the outer edge of the disc 100 (not shown in FIG. 26).

[0282]FIG. 27 is a perspective view illustrating the disc cartridge 308, on which the disc 100 has not been mounted yet, to show a state where the shutters 21 and 22 cover the chucking and head openings 11 c and 11 h. As shown in FIG. 27, the disc holders 21 a, 21 b, 22 a and 22 b protrude into the disc storage portion 10 d. Thus, when the disc 100 is stored in this disc cartridge 308, the disc 100 is held by these disc holders 21 a, 21 b, 22 a and 22 b. On the other hand, FIG. 28 is a perspective view illustrating the disc cartridge 308, on which the disc 100 has not been mounted yet, to show a state where the shutters 21 and 22 expose the chucking and head openings 11 c and 11 h. As shown in FIG. 28, while the shutters 21 and 22 are opened, the disc holders 21 a, 21 b, 22 a and 22 b are stored outside of the disc storage portion 10 d of the cartridge body 10.

[0283] Next, the structure and the operation of the shutters 21 and 22 will be described in further detail with reference to FIGS. 29, 30 and 31. FIG. 29 is a partial cross-sectional view of the disc cartridge 308, which is viewed along a plane that passes the center of the disc 100. As shown in FIG. 29, the inner side surface 12 i of the cartridge body 10 is provided with a notched portion 10 w so as not to interfere with the opening and closing operations of the shutters 21 and 22. Also, the cartridge body 10 further includes shutter storage 10 s for storing a portion of the shutters 21 and 22 being opened. Furthermore, at least the edges 21 f and 22 f of the shutters 21 and 22, which are butted against each other over the chucking and head openings 11 c and 11 h while the shutters 21 and 22 are closed, overlap with each other vertically (i.e., in the thickness direction of the disc 100) as shown in FIG. 29.

[0284] On the other hand, as shown in FIG. 30, each of the disc holders 21 a, 21 b, 22 a and 22 b includes a slope 21 a′, 21 b′, 22 a′ or 22 b′, which hangs over the projection area of the disc 100 and overlaps with the outer edge of the disc 100. That is to say, the slope 21 a′, 21 b′, 22 a′ or 22 b′ has a downwardly tapered cross section and leans toward the disc 100 as shown in FIG. 30. While the chucking and head openings 11 c and 11 h are covered with the shutters 21 and 22, the slopes 21 a′, 21 b′, 22 a′ and 22 b′ are allowed to contact with the outer edge 100 c of the disc 100, thereby gripping the disc 100 thereon and pressing the disc 100 in the thickness direction loot. As a result, the sheets 21 p and 22 p of the shutters 21 and 22 contact with the signal recording side 100A of the disc 100 and the disc 100 is fixed in the cartridge body 10. In such a state, the signal recording side 100A of the disc 100 is in close contact with the sheets 21 p and 22 p. Thus, no dust will be deposited on the signal recording side 100A.

[0285] Also, if the exposed side of the disc 100 is rotated manually or if the shutters 21 and 22 are opened or closed intentionally, then dust, finger marks or any other dirt that has adhered onto the signal recording side 100A of the disc 100 may be wiped away.

[0286] Furthermore, as shown in FIG. 31, the shutter 21 includes a shutter opener/closer 21 t, an elastic portion 21 v and a locking protrusion 21 k. These portions 21 t, 21 v and 21 k form integral parts of the shutter 21. Specifically, the shutter opener/closer 21 t is for use to open and close the shutter 21 externally. The locking protrusion 21 k is connected to the shutter 21 by way of the elastic portion 21 v. While the shutter 21 covers the chucking and head openings 11 a and 11 h, the locking protrusion 21 k, to which an elastic force is being applied from the elastic portion 21 v, engages with a locking hole 10 k of the cartridge body 10, thereby preventing the shutter 21 from rotating and fixing the shutter 21 to the cartridge body 10 as shown in FIG. 31. When the shutter 21 is fixed, the other shutter 22, which is interlocked with the former shutter 21 via the interlocking mechanism 20 c, is also fixed.

[0287] Accordingly, only by getting the locking protrusion 21 k pressed externally by a protrusion, for example, in the direction indicated by the arrow 20A and disengaged from the locking hole 10 k while pressing the opener/closer 21 t in the direction indicated by the arrow 20B at the same time, the shutters 21 and 22 can be rotated to expose the chucking and head openings 11 c and 11 h and the disc 100 can be released from the disc holders 21 a, 21 b, 22 a and 22 b. Thus, it is possible to prevent the user from removing the disc 100 accidentally.

[0288] Next, the structure and operation of the disc stoppers 23 will be described in further detail with reference to FIGS. 24 and 32. FIG. 32 is a perspective view illustrating the removable disc stopper 23 upside down. The convex portions 23 a, 23 b and 23 c of the disc stopper 23 are respectively engaged with concave portions 12 a, 12 b and 12 c provided for the upper shell 12 near the disc window 12 w thereof as shown in FIG. 24. Thus, if these convex portions 23 a, 23 b and 23 c are disengaged from the concave portions 12 a, 12 b and 12 c, the disc stopper 23 can be removed from the upper shell 12.

[0289] Next, a mechanism for preventing the user from inserting this disc cartridge 308 into a disc drive in the wrong way will be described with reference to FIG. 33. FIG. 33 is a front view illustrating the insertion side of the disc cartridge 308 shown in FIG. 23 as viewed in the direction 1B (see FIG. 23). As shown in FIG. 33, the cartridge body 10 includes a concave portion 10 g on one side surface thereof and is asymmetric in the direction 1A in which the disc cartridge 308 is inserted into the disc drive (see FIG. 23). The concave portion 10 g is not located at the center of thickness of the cartridge body 10.

[0290] By providing such a concave portion 10 g for the disc cartridge 308, only when its associated convex portion, provided for the disc drive, is fitted with this concave portion 10 g, the disc cartridge 308 can be inserted into the disc drive correctly and the disc drive can operate normally.

[0291] Stated otherwise, even if the user tries to insert the disc cartridge 308 into the disc drive upside down by mistake, he or she cannot insert the cartridge 308 into the disc drive. This is because the associated convex portion of the disc drive interferes with the other side surface of the disc cartridge 308 with no concave portion 10 g. Also, even if the user tries to insert the disc cartridge 308 into the disc drive upside down and in the wrong way by mistake, he or she cannot insert the cartridge 308 into the disc drive, either. This is because the convex portion of the disc drive also interferes with the non-recessed portion of the side surface with the concave portion 10 g. Thus, it is possible to prevent the user from inserting the disc cartridge 308 erroneously.

[0292] The disc cartridge 308 of the eighth preferred embodiment described above may be modified in various manners.

[0293] For example, the thickness of the cartridge body 10 may be further reduced to such an extent that the disc stoppers 23 will not protrude from the upper surface 12 f of the upper shell 12 (see FIG. 24) while the shutters 21 and 22 are closed. In that case, while the shutters 21 and 22 are going to be opened, the disc holders 21 a and 22 a may push the respective convex portions 23 a of the disc stoppers 23 upward from under the disc stoppers 23, thereby protruding the disc stoppers 23 from the upper surface 12 f of the upper shell 12. According to such a structure, a sufficiently broad space can be allowed the disc 100 to rotate inside the disc storage portion 10 d and yet the disc cartridge 308 can have its thickness further reduced.

[0294] Also, the disc stoppers 23 may form integral parts of the cartridge body 10. In that case, the disc stoppers 23 should be able to be bent almost perpendicularly so that the disc 100 mounted can be removed.

[0295] Furthermore, the shutter springs 31 and 32 may apply an elastic force in such a direction as to open the shutters 21 and 22. If the shutters 21 and 22 can operate almost completely synchronously by way of the interlocking mechanism, one of the shutter springs 31 and 32 may be omitted.

[0296] In the preferred embodiment described above, the locking protrusion 21 k forms an integral part of the shutter 21. Alternatively, a locking lever, including a locking protrusion and a convex portion at the end thereof, may be connected to the cartridge body 10 via an elastic portion, and an associated concave portion may be provided for the shutter so that the convex and concave portions engage with each other. In that case, by pressing the locking protrusion through a locking hole of the cartridge body, these convex and concave portions may be disengaged from each other so as to allow the shutters to rotate freely. Optionally, in that alternative preferred embodiment, the locking lever, as well as the shutter springs (i.e., elastic members), may be resin springs that form integral parts of the cartridge body 10.

[0297] Embodiment 9

[0298] Hereinafter, a disc cartridge 309 according to a ninth specific preferred embodiment of the present invention will be described with reference to the accompanying drawings.

[0299] As shown in FIGS. 34 and 35, the disc cartridge 309 includes a lower shell 41, an upper shell 42, disc stoppers 42 a, 42 b, 42 c and 42 d, and a pair of shutters 51 and 52.

[0300] As shown in FIG. 35, the lower shell 41 includes a chucking opening 41 c and a head opening 41 h. The chucking opening 41 c allows a chucking member (e.g., a spindle motor for rotating the disc 100) to enter the disc cartridge 309 externally. The head opening 41 h allows a head, which reads and/or writes a signal from/on the signal recording side 100A of the disc 100, to enter the disc cartridge 309 and access a target location on the disc 100. The lower shell 41 faces the signal recording side 100A of the disc 100. Also, the head opening 41 h reaches one side surface of the lower shell 41.

[0301] The upper shell 42 includes a circular disc window 42 w, through which the disc 100 can be introduced and removed into/from the disc cartridge 309 and which expands over the entire projection area of the disc 100 to expose the upper side of the disc 100. The upper and lower shells 42 and 41 are adhered or welded together at their outer periphery, thereby forming a cartridge body 40.

[0302] A disc storage portion 40 d for storing the disc 100 therein is defined by a first inner surface 41 u and a second inner surface 42 i of the cartridge body 40. The first inner surface 41 u is opposed to the signal recording side 100A of the disc 100, while the second inner surface 42 i has a substantially cylindrical shape and defines the disc window 42 w inside. That is to say, the first inner surface 41 u is the bottom of the disc storage portion 40 d.

[0303] In the disc storage portion 40 d, a gap, which is wide enough to allow the disc 100 to rotate freely, is provided between the second inner surface 42 i and the outer periphery of the disc 100. Also, the top of the disc storage portion 40 d is the disc window 42 w so that the disc 100 stored in the disc storage portion 40 d has one of its sides exposed inside the disc window 42 w.

[0304] The disc stoppers 42 a, 42 b, 42 c and 42 d form integral parts of the upper shell 42 so as to partially protrude into the disc window 42 w. Each of these disc stoppers 42 a, 42 b, 42 c and 42 d is separated from the upper shell 42 via a slit. These disc stoppers 42 a, 42 b, 42 c and 42 d are used to prevent the disc 100 from dropping down from the disc window 42 w. The disc stoppers 42 a, 42 b, 42 c and 42 d are effective particularly when this disc cartridge 309 is loaded into a vertically mounted disc drive. Optionally, these disc stoppers 42 a, 42 b, 42 c and 42 d may be integrated with the upper shell 42 by way of elastic members.

[0305] The shutters 51 and 52 are disposed between the signal recording side 100A of the disc 100 and the first inner surface 41 u of the cartridge body 40. The shutters 51 and 52 include shaft holes 51 u and 52 u, respectively. These shaft holes 51 u and 52 u are engaged in a freely rotatable state with shafts 41 s, which are located outside of the disc storage portion 40 d of the cartridge body 40 and on a deep side of the cartridge body 40 opposite to the head opening 41 h thereof. Thus, the shutters 51 and 52 rotate on the shafts 41 s in such a manner as to cover or expose the chucking and head openings 41 c and 41 h.

[0306] A cam 51 c and a follower 52 c are provided near the shaft holes 51 u and 52 u of the shutters 51 and 52, respectively. The cam 51 c and the follower 52 c have mutually engaging shapes and together make up an interlocking mechanism 50 c for opening and closing the shutters 51 and 52 while interlocking them with each other.

[0307] The respective upper surfaces of the shutters 51 and 52, which are opposed to the signal recording side 100A of the disc 100, are covered with protective layers 51 p and 52 p for the purpose of preventing the signal recording side 100A of the disc 100 from getting scratched or attracting dust.

[0308] The protective layers 51 p and 52 p may be appropriately selected from the group consisting of anti-scratching nonwoven fabric, dustproof nonwoven fabric, anti-scratching coating and dustproof coating. In this preferred embodiment, sheets of a dustproof nonwoven fabric are adhered or ultrasonic welded as the protective layers 51 p and 52 p to the shutters 51 and 52, respectively.

[0309] Shutter springs 61 and 62 are provided outside of the disc storage portion 40 d for the shutters 51 and 52, respectively. These springs 61 and 62 apply an elastic force to the shutters 51 and 52 in such a direction as to close the shutters 51 and 52. Alternatively, the shutter springs 61 and 62 may apply an elastic force to the shutters 51 and 52 in such a direction as to open the shutters 51 and 52. Also, if the shutters 51 and 52 can operate almost completely synchronously by way of the interlocking mechanism, one of the shutter springs 61 and 62 may be omitted.

[0310] As in the eighth preferred embodiment described above, the shutters 51 and 52 each include two disc holders 51 a, 51 b and 52 a, 52 b at both ends thereof as shown in FIG. 35.

[0311] Furthermore, as will be described in detail later, convex portions 51 e and 52 e are formed on the shutters 51 and 52, respectively, so as to be located under the center hole of the disc 100 while the shutters 51 and 52 are closed. As shown in FIG. 34, the upper surface of the cartridge body 40 (or the upper shell 42) has embossed arrow marks (or concave portions) 40 a that indicate the direction (the arrow 1A) in which this disc cartridge 309 should be inserted into a disc drive. The cartridge body 40 further includes two concave portions 40 c on two of its side surfaces that are parallel to the direction 1A in which the disc cartridge 309 is inserted into the disc drive. These concave portions 40 c may be used as either pull-in notches or positioning recesses when the disc cartridge 309 is pulled in and loaded into a disc drive or when the disc cartridge 309 is stored in a disc changer. Optionally, only one of the side surfaces of the disc cartridge 309 may include the concave portion 40 c. In that case, the concave portion 40 c can contribute to preventing the user from inserting or loading this disc cartridge 309 into the disc drive upside down by mistake. The upper surface of the cartridge body 40 further includes a grip 40 e that allows the user to grip this disc cartridge 309. This grip 40 e has an antislip embossed shape.

[0312]FIG. 36 is a perspective view illustrating the disc cartridge 309, in which no disc 100 has been stored yet, to show a state where the shutters 51 and 52 cover the chucking and head openings 41 c and 41 h. FIG. 37 is a perspective view illustrating the disc cartridge 309, in which no disc 100 has been stored yet, to show a state where the shutters 51 and 52 expose the chucking and head openings 41 c and 41 h.

[0313] Hereinafter, the structure and the operation of the shutters 51 and 52 will be described in further detail. As shown in FIGS. 34 and 35, the disc holders 51 a, 51 b, 52 a and 52 b of the shutters 51 and 52 also have such a cross-sectional shape as including a slope that hangs over the projection area of the disc 100 and overlaps with the outer edge of the disc 100 as in the eighth preferred embodiment. That is to say, the slope is downwardly tapered and leans toward the disc 100. Thus, the effects of the eighth preferred embodiment described above are also achieved by this ninth preferred embodiment.

[0314] Also, the shutter 52 includes an opener/closer 52 t for use to open and close the shutter 52 externally, while the shutter 51 includes an elastic portion 51 v and a locking protrusion 51 k as integral parts thereof. The locking protrusion 51 k is connected to the shutter 51 by way of the elastic portion 51 v as shown in FIG. 35. Thus, while the chucking and head openings 41 c and 41 h are covered with the shutters 51 and 52, the locking protrusion 51 k, to which an elastic force is applied from the elastic portion 51 v, engages with a locking hole 40 k of the cartridge body 40 (or the lower shell 41), thereby fixing the shutter 51 in a non-rotatable state to the cartridge body 40. When the shutter 51 is fixed in this way, the other shutter 52, which is interlocked with the shutter 51 via the interlocking mechanism 50 c, is also fixed.

[0315] Accordingly, only by getting the locking protrusion 51 k pressed externally by a protrusion, for example, in the direction indicated by the arrow 50A and disengaged from the locking hole 40 k while pressing the opener/closer 52 t in the direction indicated by the arrow 50B at the same time as shown in FIG. 36, the shutters 51 and 52 can be rotated to expose the chucking and head openings 41 c and 41 h and the disc 100 can be released from the disc holders 51 a, 51 b, 52 a and 52 b. Thus, it is possible to prevent the user from removing the disc 100 accidentally.

[0316] Unlike the eighth preferred embodiment described above, the locking protrusion 51 k and the opener/closer 52 t are provided in this preferred embodiment for the two different shutters 51 and 52. Such a structure is particularly effective for a disc cartridge for a disc of a small size. This is because a disc cartridge for a disc of a small size and the shutters thereof should have relatively small sizes and it is normally difficult to provide the locking protrusion and opener/closer for a single shutter out of design considerations. Also, even when a single shutter can include both the locking protrusion and the opener/closer, a very narrow gap would be allowed between a shutter opening/closing mechanism and an unlocking mechanism on the disc drive side or these two mechanisms need to be formed within a very limited space, thus making it hard to design the disc drive as intended.

[0317] In the preferred embodiment described above, the locking protrusion 51 k forms an integral part of the shutter 51. Alternatively, a locking lever, including a locking protrusion and a convex portion at the end thereof, may be connected to the cartridge body 40 by way of an elastic portion, and an associated concave portion may be provided for the shutter so that the convex and concave portions engage with each other. In that case, by pressing the locking protrusion through a locking hole of the cartridge body, these convex and concave portions may be disengaged from each other so as to allow the shutters to rotate freely. Optionally, in that alternative preferred embodiment, the locking lever, as well as the shutter springs (i.e., elastic members), may be resin springs that form integral parts of the cartridge body 40.

[0318] Next, it will be described how the convex portions 51 e and 52 e on the shutters 51 and 52 work. FIG. 38 is a partial cross-sectional view of the disc cartridge 309, which is viewed along a plane that passes the center of the disc 100. As shown in FIG. 38, while the shutters 51 and 52 are closed, the convex portions 51 e and 52 e protrude into the center hole 100 h of the disc 100 and the disc 100 is now in contact with the shutters 51 and 52.

[0319] As shown in FIG. 39, while the shutters 51 and 52 are going to be opened, the convex portions 51 e and 52 e slide from inside the center hole 100 h into under the lower side of the disc 100, thereby lifting the disc 100 up from the shutters 51 and 52. In this manner, while the shutters 51 and 52 are going to be opened or closed, the signal recording side 100A of the disc 100 will not get scratched by the shutters 51 and 52. Also, it is inside the signal recording area of the signal recording side 100A that the convex portions 51 e and 52 e move along with the shutters 51 and 52 being opened or closed. Accordingly, the convex portions 51 e and 52 e will not contact with, or scratch, the signal recording area.

[0320] Next, the structure and operation of the disc stoppers will be described with reference to FIGS. 40 and 41. FIG. 40 is a partial cross-sectional view illustrating a portion of the disc cartridge 309 around the disc outer periphery, and is viewed along a plane that passes the center of the disc 100. As shown in FIG. 40, a convex portion 42 a′, 42 b′, 42 c′ or 42 d′ has been formed on the bottom of the disc stopper 42 a, 42 b, 42 c or 42 d. While the shutters 51 and 52 are closed, the disc stopper 42 a, 42 b, 42 c or 42 d is substantially parallel to the surface of the disc 100 and falls within the thickness of the cartridge 309 as shown in FIG. 40. An appearance of the disc cartridge 309 in such a state is illustrated in FIG. 36.

[0321] On the other hand, while the shutters 51 and 52 are opened, the slopes 52 f, 51 f, 51 d and 52 d of the shutters 51 and 52 contact with the convex portions 42 a′, 42 b′, 42 c′ and or 42 d′, respectively, thereby lifting the disc stoppers 42 a, 42 b, 42 c and 42 d to above the disc 100 as shown in FIG. 41. An appearance of the disc cartridge 309 in such a state is illustrated in FIG. 37. By using such a structure, particularly in an interval after the disc cartridge 309 has been vertically loaded into a disc drive and before the disc 100 is chucked, it is possible to prevent the disc 100 from dropping down from the cartridge 309. In addition, while the disc 100 is being chucked, the disc 100 can move in a broader space. Furthermore, this structure can also contribute to further reducing the thickness of the cartridge.

[0322] It should be noted that to keep the shutters 51 and 52 temporarily opened for a while, the slopes 52 f, 51 f, 51 d and 52 d may have convex or concave portions that engage with the convex portions 42 a′, 42 b′, 42 c′ and 42 d′.

[0323] Embodiment 10

[0324] Hereinafter, a disc cartridge 310 according to a tenth specific preferred embodiment of the present invention will be described with reference to the accompanying drawings. The disc cartridge 310 of this preferred embodiment is mainly characterized in that disc stoppers are provided for the shutters.

[0325] As shown in FIGS. 42 and 43, the disc cartridge 310 includes a lower shell 71, an upper shell 72, disc stoppers 81 d, 81 f, and 82 d, and a pair of shutters 81 and 82.

[0326] As shown in FIG. 43, the lower shell 71 includes a chucking opening 71 c and a head opening 71 h. The chucking opening 71 c allows a chucking member (e.g., a spindle motor for rotating the disc 100) to enter the disc cartridge 310 externally. The head opening 71 h allows a head, which reads and/or writes a signal from/on the signal recording side 100A of the disc 100, to enter the disc cartridge 310 and access a target location on the disc 100. The lower shell 71 faces the signal recording side 100A of the disc 100. Also, the head opening 71 h reaches one side surface of the lower shell 71.

[0327] The upper shell 72 includes a circular disc window 72 w, through which the disc 100 can be introduced and removed into/from the disc cartridge 310 and which expands over the entire projection area of the disc 100 to expose the upper side of the disc 100. The upper and lower shells 72 and 71 are adhered or welded together at their outer periphery, thereby forming a cartridge body 70.

[0328] A disc storage portion 70 d for storing the disc 100 therein is defined by a first inner surface 71 u and a second inner surface 721 of the cartridge body 70. The first inner surface 71 u is opposed to the signal recording side 100A of the disc 100, while the second inner surface 721 has a substantially cylindrical shape and defines the disc window 72 w inside. That is to say, the first inner surface 71 u is the bottom of the disc storage portion 70 d.

[0329] In the disc storage portion 70 d, a gap, which is wide enough to allow the disc 100 to rotate freely, is provided between the second inner surface 72 i and the outer periphery of the disc 100. Also, the top of the disc storage portion 70 d is the disc window 72 w so that the disc 100 stored in the disc storage portion 70 d has one of its sides exposed inside the disc window 72 w.

[0330] The shutters 81 and 82 are disposed between the signal recording side 100A of the disc 100 and the first inner surface 71 u of the cartridge body 70. The shutters 81 and 82 include shaft holes 81 u and 82 u, respectively. These shaft holes 81 u and 82 u are engaged in a freely rotatable state with shafts 71 s, which are located outside of the disc storage portion 70 d of the cartridge body 70 and on a deep side of the cartridge body 70 opposite to the head opening 71 h thereof. Thus, the shutters 81 and 82 rotate on the shafts 71 s in such a manner as to cover or expose the chucking and head openings 71 c and 71 h.

[0331] A cam 81 c and a follower 82 c are provided near the shaft holes 81 u and 82 u of the shutters 81 and 82, respectively. The cam 81 c and the follower 82 c have mutually engaging shapes and together make up an interlocking mechanism 80 c for opening and closing the shutters 81 and 82 while interlocking them with each other.

[0332] The respective upper surfaces of the shutters 81 and 82, which are opposed to the signal recording side 100A of the disc 100, are covered with protective layers 81 p and 82 p for the purpose of preventing the signal recording side 100A of the disc 100 from getting scratched or attracting dust.

[0333] The protective layers 81 p and 82 p may be appropriately selected from the group consisting of anti-scratching nonwoven fabric, dustproof nonwoven fabric, anti-scratching coating and dustproof coating. In this preferred embodiment, sheets of a dustproof nonwoven fabric are adhered or ultrasonic welded as the protective layers 81 p and 82 p to the shutters 81 and 82, respectively.

[0334] Shutter springs 91 and 92 are provided outside of the disc storage portion 70 d for the shutters 81 and 82, respectively. These springs 91 and 92 apply an elastic force to the shutters 81 and 82 in such a direction as to close the shutters 81 and 82. Alternatively, the shutter springs 91 and 92 may apply an elastic force to the shutters 81 and 82 in such a direction as to open the shutters 81 and 82. Also, if the shutters 81 and 82 can operate almost completely synchronously by way of the interlocking mechanism 80 c, one Of the shutter springs 91 and 92 may be omitted.

[0335] As in the eighth preferred embodiment described above, the shutters 81 and 82 each include two disc holders 81 a, 81 b and 82 a, 82 b at both ends thereof as shown in FIG. 43. Convex portions 81 e and 82 e are also formed on the shutters 81 and 82, respectively, as in the ninth preferred embodiment.

[0336] Furthermore, as will be described in detail later, the disc stoppers 81 f, 81 d and 82 d are provided as integral parts of the shutters 81 and 82 near the disc holders 81 a, 81 b and 82 a, respectively. Alternatively, these disc stoppers 81 f, 81 d and 82 d may be integrated with the shutters 81 and 82 by way of elastic members.

[0337] As shown in FIG. 42, the upper surface of the cartridge body 70 (or the upper shell 72) has embossed arrow marks (or concave portions) 70 a that indicate the direction (the arrow 1A) in which this disc cartridge 310 should be inserted into a disc drive. The cartridge body 70 further includes two concave portions 70 c on two of its side surfaces that are parallel to the direction 1A in which the disc cartridge 310 is inserted. These concave portions 70 c may be used as either pull-in notches or positioning recesses when the disc cartridge 310 is pulled in and loaded into a disc drive or when the disc cartridge 310 is stored in a disc changer. Optionally, only one of the side surfaces of the disc cartridge 310 may include the concave portion 70 c. In that case, the concave portion 70 c can contribute to preventing the user from inserting or loading this disc cartridge 310 into the disc drive upside down by mistake. The upper surface of the cartridge body 70 further includes a grip 70 e that allows the user to grip this disc cartridge 310. This grip 70 e has an antislip embossed shape.

[0338]FIG. 44 is a perspective view illustrating the disc cartridge 310, in which no disc 100 has been stored yet, to show a state where the shutters 81 and 82 cover the chucking and head openings 71 c and 71 h. FIG. 45 is a perspective view illustrating the disc cartridge 310, in which no disc 100 has been stored yet, to show a state where the shutters 81 and 82 expose the chucking and head openings 71 c and 71 h.

[0339] Hereinafter, the structure and the operation of the shutters 81 and 82 will be described in further detail. As shown in FIGS. 42 and 43, the disc holders 81 a, 81 b, 82 a and 82 b of the shutters 81 and 82 have such a cross-sectional shape as including a slope that hangs over the projection area of the disc 100 and overlaps with the outer edge of the disc 100 as in the eighth preferred embodiment. That is to say, the slope is downwardly tapered and leans toward the disc 100. Thus, the effects of the eighth preferred embodiment described above are also achieved by this tenth preferred embodiment.

[0340] Also, the shutter 82 includes an opener/closer 82 t for use to open and close the shutter 82 externally, an elastic portion 82 v and a locking protrusion 82 k as integral parts thereof. The locking protrusion 82 k is connected to the shutter 82 by way of the elastic portion 82 v as shown in FIG. 43. Thus, while the chucking and head openings 71 c and 71 h are covered with the shutters 81 and 82, the locking protrusion 82 k, to which an elastic force is applied from the elastic portion 82 v, engages with a locking hole 70 k of the cartridge body 70 (or the lower shell 71) as shown in FIG. 44, thereby fixing the shutter 82 in a non-rotatable state to the cartridge body 70. When the shutter 82 is fixed in this way, the other shutter 81, which is interlocked with the shutter 82 via the interlocking mechanism 80 c, is also fixed.

[0341] Accordingly, only by getting the locking protrusion 82 k pressed externally by a protrusion, for example, in the direction indicated by the arrow 70A and disengaged from the locking hole 70 k while pressing the opener/closer 82 t in the direction indicated by the arrow 70B at the same time as shown in FIG. 44, the shutters 81 and 82 can be rotated to expose the chucking and head openings 71 c and 71 h and the disc 100 can be released from the disc holders 81 a, 81 b, 82 a and 82 b. Thus, it is possible to prevent the user from removing the disc 100 accidentally.

[0342] In the preferred embodiment described above, the locking protrusion 82 k forms an integral part of the shutter 82. Alternatively, a locking lever, including a locking protrusion and a convex portion at the end thereof, may be connected to the cartridge body 70 by way of an elastic portion, and a concave portion may be provided for the shutter so that the convex and concave portions engage with each other. In that case, by pressing the locking protrusion through a locking hole of the cartridge body, these convex and concave portions may be disengaged from each other so as to allow the shutters to rotate freely. Optionally, in that alternative preferred embodiment, the locking lever, as well as the shutter springs (i.e., elastic members), may be resin springs that form integral parts of the cartridge body 70.

[0343] Next, the structure and operation of the disc stoppers 81 f, 81 d and 82 d will be described in further detail. While the shutters 81 and 82 are closed, the disc stoppers 81 f, 81 d and 82 d are substantially parallel to the surface of the disc 100 and do not protrude from the upper surface of the disc cartridge 310 as shown in FIGS. 46 and 48. An appearance of the disc cartridge 310 in such a state is illustrated in FIG. 44.

[0344] On the other hand, while the shutters 81 and 82 are going to be opened, the disc stoppers 81 f, 81 d and 82 d are guided by a slit 70 s and a slope 72 s of the cartridge body 70 so as to be lifted to above the disc 100 as shown in FIGS. 47 and 49. The slit 70 s is formed in the inner sidewall of the cartridge body 70 as shown in FIG. 47, while the slope 72 s is formed on the inner upper surface of the cartridge body 70 as shown in FIG. 49. Also, the upper shell 72 is provided with notched portions 72 a, 72 b and 72 c so as not to interfere with the disc stoppers 81 f, 81 d and 82 d that have been lifted up. An appearance of the disc cartridge 310 in such a state is illustrated in FIG. 45.

[0345] While the shutters 81 and 82 are closed, the disc stoppers 81 f, 81 d and 82 d hang over the projection area of the disc 100 and overlap with the outer periphery of the disc 100. Thus, the disc stoppers 81 f, 81 d and 82 d press the disc 100 against the shutters 81 and 82 in the thickness direction, thereby holding it thereon. Accordingly, the disc holders 81 a, 81 b, 82 a and 82 b may be omitted from the shutters 81 and 82.

[0346] By using such a structure, particularly in an interval after the disc cartridge 310 has been vertically loaded into a disc drive and before the disc 100 is chucked, it is possible to prevent the disc 100 from dropping down from the cartridge 310. In addition, while the disc 100 is being chucked, the disc 100 can move in a broader space. Furthermore, this structure can also contribute to further reducing the thickness of the cartridge body.

[0347] Embodiment 11

[0348] Hereinafter, a disc cartridge 311 according to an eleventh specific preferred embodiment of the present invention will be described with reference to the accompanying drawings.

[0349] As shown in FIGS. 50 and 51, the disc cartridge 311 includes a lower shell 11, an upper shell 12, a pair of shutters 21 and 22 and disc stoppers 23. As shown in FIGS. 52 through 56, the structures and functions of all of these members are the same as those already described for the eighth preferred embodiment and the detailed description thereof will be omitted herein.

[0350] Unlike the disc-cartridge 308 of the eighth preferred embodiment described above, the shutters 21 and 22 of the disc cartridge 311 of the eleventh preferred embodiment have a hole 20 h as shown in FIGS. 50 and 51.

[0351] More specifically, while the shutters 21 and 22 of the disc cartridge 311 are closed, the shutters 21 and 22 define the hole 20 h just under the center hole 10 h of the disc 100 as shown in FIG. 50. As can be seen from FIG. 51, the hole 20 h is made up of two notches 21 h and 22 h of the shutters 21 and 22, respectively.

[0352] If the disc cartridge 311 is left with the upper side of the disc 100 exposed upward as shown in FIG. 50, dust may pass through the center hole 100 h of the disc 100. Even so, in this structure, the dust should pass and go out through the hole 20 h of the shutters 21 and 22 without remaining in the disc cartridge 311, or without being deposited on the shutters 21 and 22. Thus, when the shutters 21 and 22 are opened after that (i.e., when this disc cartridge 311 has been loaded into a disc drive), no dust will be deposited on the signal recording side 100A of the disc 100.

[0353] The disc cartridge 311 may be left either upside up as shown in FIG. 50 or upside down (i.e., with the lower shell 11 facing upward). In view of these two possible positions, the hole 20 h preferably has a diameter that is approximately equal to that of the center hole 100 h. This is because if the holes 20 h and 100 h have approximately equal diameters, dust will be deposited neither on the shutters 21 and 22 when the disc cartridge 311 is left upside up nor on the signal recording side 100A of the disc 100 when the disc cartridge 311 is left upside down.

[0354] In this disc cartridge 311, the opener/closer 22 t for use to open and close the shutters 21 and 22 is provided for the shutter 22 unlike the eighth preferred embodiment described above. More specifically, as shown in FIGS. 51 and 57, the opener/closer 22 t, elastic portion 22 v and locking protrusion 22 k are provided as integral parts of the shutter 22. The locking protrusion 22 k is connected to the shutter 22 by way of the elastic portion 22 v as shown in FIG. 57. Accordingly, unlike the eighth preferred embodiment described above, the opener/closer 22 t is located on the right-hand side of the head opening 11 h with respect to the disc 100. The opener/closer 22 t operates in the same way as the counterpart of the eighth preferred embodiment described above.

[0355] Embodiment 12

[0356] Hereinafter, a disc cartridge 312 according to a twelfth specific preferred embodiment of the present invention will be described with reference to the accompanying drawings.

[0357] Unlike the disc cartridge 311 of the eleventh preferred embodiment described above, the disc cartridge 312 of this twelfth preferred embodiment includes a rim 12 t around the inner side surface 12 i of the cartridge body 10 and a ring 20 w around the hole 20 h defined by the shutters 21 and 22. These features will be described below.

[0358] As shown in FIG. 58, the rim 12 t protrudes from the inner side surface 12 i of the upper shell 12 toward the inner periphery of the disc 100 and substantially surrounds the outer periphery of the disc storage portion 10 d. FIG. 59 shows a cross section of the disc cartridge 312 in a state where the disc 100 is stored in the disc storage portion 10 d. While the shutters 21 and 22 are closed, the outer edge of the signal recording side 100A of the disc 100 contacts with the rim 12 t as shown in FIG. 59. As a result, the gap between the outer periphery of the disc 100 and the cartridge body 10 is closed, thereby preventing dust from reaching the signal recording side 100A of the disc 100.

[0359] Also, a gap 10 w is provided between the rim 12 t of the cartridge body 10 and the lower shell 11. Thus, when the shutters 21 and 22 are opened, respective portions of the shutters 21 and 22 enter the gap 10 w as shown in FIGS. 60 and 61, thereby preventing the shutters 21 and 22 from interfering with the cartridge body 10.

[0360] In such a structure, however, while the shutters 21 and 22 are closed, another gap 10 z that leads to the open air is also created between the disc 100 and the shutters 21 and 22 as shown in FIG. 59. To close this gap 10 z, the shutters 21 and 22 include convex portions 21 w and 22 w, respectively, around the center hole 100 h of the disc 100. As shown in FIG. 58, when the shutters 21 and 22 are closed, these two convex portions 21 w and 22 w are in tight contact with each other, thereby forming the ring 20 w that closes the gap 10 z around the disc center hole 100 h. As a result, no dust will reach the signal recording side 100A of the disc 100 through the disc center hole 100 h.

[0361] However, the top of these convex portions 21 w and 22 w might contact with the signal recording side 100A of the disc 100. Accordingly, the edge of the convex portions 21 w and 22 w should preferably be round so as not to scratch the signal recording side 100A of the disc 100. Optionally, the convex portions 21 w and 22 w may form integral parts of the shutters 21 and 22, respectively. In that case, an anti-scratching nonwoven fabric is preferably adhered or ultrasonic welded to that portion of the ring 20 w that contacts with the signal recording side 10A of the disc 100 or an anti-scratching coating is preferably formed on that portion. Alternatively, the convex portions 21 w and 22 w themselves may be made of an anti-scratching nonwoven fabric or an anti-scratching coating and directly adhered or ultrasonic welded to the shutters 21 and 22, respectively.

[0362] Also, as shown in FIG. 59, while the shutters 21 and 22 are closed, the disc 100 is lifted by the ring 20 w and the rim 12 t over the shutters 21 and 22 with the gap 10 z left between them. That is to say, most of the signal recording side 100A of the disc 100 is not in contact with the shutters 21 and 22. Accordingly, even if the surface of the shutters 21 and 22 is not covered with an anti-scratching nonwoven fabric, for example, the signal recording side 100A still will not get scratched.

[0363]FIGS. 62 and 63 illustrate a disc cartridge including alternative convex portions 21 w′ and 22 w′ that have been expanded toward the outer periphery of the disc 100. Specifically, FIG. 62 illustrates a state in which the shutters 21 and 22 are closed, while FIG. 63 illustrates a state in which the shutters 21 and 22 are opened.

[0364] As shown in FIGS. 62 and 63, while the shutters 21 and 22 are opened, the convex portions 21 w′ and 22 w′ are preferably located inside the rim 12 t of the disc storage portion 10 d (i.e., closer to the center of the disc storage portion 10 d). Then, the convex portions 21 w′ and 22 w′ will not contact with, or interfere with, the rim 12 t.

[0365] Optionally, the convex portions 21 w′ and 22 w′ may form integral parts of the shutters 21 and 22, respectively. In that case, an anti-scratching nonwoven fabric is preferably adhered or ultrasonic welded to those portions of the convex portions 21 w′ and 22 w′ that contact with the disc 100 or an anti-scratching coating is preferably formed thereon. Alternatively, the convex portions 21 w′ and 22 w′ themselves may be made of an anti-scratching nonwoven fabric or an anti-scratching coating and directly adhered or ultrasonic welded to the shutters 21 and 22, respectively.

[0366] Embodiment 13

[0367] Hereinafter, a disc cartridge 313 according to a thirteenth specific preferred embodiment of the present invention will be described with reference to the accompanying drawings.

[0368] First, the structure of the disc cartridge 313 will be outlined with reference to FIGS. 64 and 65. As in the eighth preferred embodiment, the disc 100 shown in FIGS. 64 and 65 also includes first and second sides. The first side of the disc 100, on which its label is normally printed, is illustrated in FIG. 64, while the second side thereof, i.e., the signal recording side 100A, is illustrated as the backside in FIG. 65.

[0369] As shown in FIGS. 64 and 65, the disc cartridge 313 includes a lower shell 11, an upper shell 12, a pair of shutters 21 and 22 and disc stoppers 23.

[0370] As shown in FIG. 65, the lower shell 11 includes a chucking opening 11 c and a head opening 11 h. The chucking opening 11 a allows a chucking member (e.g., a spindle motor for rotating the disc 100) to enter the disc cartridge 313 externally. The head opening 11 h allows a head, which reads and/or writes a signal from/on the signal recording side 100A of the disc 100, to enter the disc cartridge 313 and access a target location on the disc 100. The lower shell 11 faces the signal recording side 100A of the disc 100. The lower shell 11 is formed by molding a synthetic resin into a predetermined shape.

[0371] The head opening 11 h reaches one side surface of the lower shell 11. To minimize a decrease in rigidity of the lower shell 11 due to the presence of the head opening 11 h, the lower shell 11 includes a bridge 11 b that links both ends of the head opening 11 h together. The lower shell 11 further includes two positioning holes 11 w that engage with cartridge positioning pins (not shown) of a disc drive.

[0372] The upper shell 12 includes a circular disc window 12 w, through which the disc 100 can be introduced and removed into/from the disc cartridge 313 and which expands over the entire projection area of the disc 100 to expose the upper side of the disc 100. The upper and lower shells 12 and 11 are adhered or welded together at their outer periphery, thereby forming a cartridge body 10. The upper shell 12 is also made of a synthetic resin.

[0373] A disc storage portion 10 d for storing the disc 100 therein is defined by an inner lower surface 11 u and an inner side surface 12 i of the cartridge body 10. The inner lower surface 11 u is opposed to the signal recording side 100A of the disc 100, while the inner side surface 12 i has a substantially cylindrical shape and defines the disc window 12 w inside. That is to say, the inner lower surface 11 u is the bottom of the disc storage portion 10 d.

[0374] In the disc storage portion 10 d, a gap, which is wide enough to allow the disc 100 to rotate freely, is provided between the inner side surface 12 i and the outer periphery of the disc 100. Also, the top of the disc storage portion 10 d is the disc window 12 w so that the disc 100 stored in the disc storage portion 10 d has one of its sides exposed inside the disc window 12 w.

[0375] Two removable disc stoppers 23 are provided for the upper shell 12 so as to partially protrude into the disc window 12 w as shown in FIGS. 64 and 65. A third disc stopper 12 s is further provided for the upper shell 12 so as to protrude into the disc window 12 w. The third disc stopper 12 s forms an integral part of the upper shell 12. These three disc stoppers 23 and 12 s are arranged substantially at regular intervals around the circumference of the disc window 12 w for the purpose of preventing the disc 100 from dropping down from the disc window 12 w. Also, two convex disc contact portions 12 s' are formed on the disc stopper 12 s. For the disc 100, these disc contact portions 12 s' are almost as high as the disc contact portions 23 a of the disc stoppers 23.

[0376] According to this structure, even if the disc cartridge 313 is mounted vertically or upside down, the disc cartridge 313 still can hold the disc 100 without dropping it. That is to say, when the disc cartridge 313 is inserted vertically or upside down into a disc drive, this disc cartridge 313 can particularly effectively prevent the disc 100 from dropping down. It should be noted that the disc stoppers 23 do not have to be removable from the cartridge body 10. Alternatively, as long as the disc stoppers 23 can be rotated or bent inside the disc storage portion 10 d to such an extent as to allow the user to remove the disc 100 from the cartridge body 10, the disc stoppers 23 may also be secured to the upper shell 12.

[0377] The shutters 21 and 22 lie on a single plane between the signal recording side 100A of the disc 100 and the inner lower surface 11 u of the cartridge body 10. The shutters 21 and 22 include shaft holes 21 u and 22 u, respectively. These shaft holes 21 u and 22 u are engaged in a freely rotatable state with shafts 11 s, which are located outside of the disc storage portion 10 d of the cartridge body 10 and on a deep side of the cartridge body 10 opposite to the head opening 11 h thereof. Thus, the shutters 21 and 22 rotate on the shafts 11 s in such a manner as to cover or expose the chucking and head openings 11 c and 11 h. The shutters 21 and 22 are also made of a synthetic resin.

[0378] A ring portion 21 c and a pin portion 22 c are provided near the shaft holes 21 u and 22 u of the shutters 21 and 22, respectively. The ring portion 21 c and the pin portion 22 c have mutually engaging shapes and together make up an interlocking mechanism 20 c for opening and closing the shutters 21 and 22 while interlocking them with each other. The interlocking mechanism 20 c may also be implemented as a cam mechanism or a gear mechanism.

[0379] The respective upper surfaces of the shutters 21 and 22, which are opposed to the signal recording side 100A of the disc 100, are covered with protective layers 21 p and 22 p for the purpose of preventing the signal recording side 100A of the disc 100 from getting scratched or attracting dust.

[0380] The protective layers 21 p and 22 p may be appropriately selected from the group consisting of anti-scratching nonwoven fabric, dustproof nonwoven fabric, anti-scratching coating and dustproof coating. In this preferred embodiment, sheets of a dustproof nonwoven fabric are adhered or ultrasonic welded as the protective layers 21 p and 22 p to the shutters 21 and 22, respectively.

[0381] A locking protrusion 21 k is provided for the shutter 21, while a locking engaging portion 22 k, which engages with the locking protrusion 21 k, is provided for the shutter 22. The locking protrusion 21 k and locking engaging portion 22 k together make up a locking mechanism 20 k for locking and unlocking the shutters 21 and 22 to/from each other. By using this mechanism 20 k, the shutters 21 and 22 can be locked and unlocked automatically, thus preventing the user from opening the shutters 21 and 22 accidentally. In addition, the signal recording side 100A of the disc 100 can be protected from dust, finger marks or scratches. The locking protrusion 21 k and the locking engaging portion 22 k form integral parts of the shutters 21 and 22, respectively.

[0382] Furthermore, the shutters 21 and 22 are provided with notches 21 h and 22 h, respectively. When the shutters 21 and 22 are closed, these notches 21 h and 22 h contact with each other to form a hole 20 h just under the center hole 100 h of the disc 100. In this case, the diameter of the hole 20 h is approximately equal to that of the center hole 100 h of the disc 100. In such a structure, even if this disc cartridge 313 is left with the upper side of the disc 100 exposed upward, no dust will be deposited on the shutters 21 and 22. Also, even if the disc cartridge 313 is left upside down, no dust will be directly deposited on the signal recording side 100A of the disc 100, either.

[0383] As already described for the eighth preferred embodiment, the shutters 21 and 22 each include two disc holders 21 a, 21 b and 22 a, 22 b at both ends thereof. These disc holders 21 a, 21 b, 22 a and 22 b are arranged substantially at regular intervals around the circumference of the disc 100. The disc holders 21 a, 21 b, 22 a and 22 b form integral parts of the shutters 21 and 22. Each of these disc holders 21 a, 21 b, 22 a and 22 b has a downwardly tapered cross-sectional shape (or slope) to grip the outer edge of the disc 100 thereon when the shutters 21 and 22 are closed. By providing these slopes, the disc 100 can be held firmly and pressed against the shutters 21 and 22 while the shutters 21 and 22 are closed.

[0384] In this preferred embodiment, only the disc holder 21 b is not secured to the shutter 21 but is connected thereto via an elastic portion 21 d and is freely rotatable in the radial direction of the disc 100 (i.e., toward the center of the disc 100). Accordingly, the disc holders 21 a, 21 b, 22 a and 22 b can firmly hold a disc 100 having any of various diameters or thicknesses without allowing the disc 100 to move inconstantly.

[0385] A shutter opener/closer 22 t for use to open and close the shutter 22 is formed as an integral part of the shutter 22 on the front side of the disc cartridge 313 opposite to the shaft hole 22 u, i.e., near the disc holder 22 a. When the shutters 21 and 22 are attached to the cartridge body 10, the shutter opener/closer 22 t is located under the bridge 11 b and inside the head opening 11 h. In opening or closing the shutters 21 and 22, the opener/closer 22 t is moved along the bridge 11 b inside the head opening 11 h. In this arrangement, there is no need to separately provide any gap for allowing the shutter opener/closer 21 t to move therein for the cartridge body 10. In other words, since there is no need to provide an extra gap for the cartridge body 10, no dust will enter the cartridge body 10 unnecessarily. Furthermore, the shutter opener/closer 22 t can be disposed inside the head opening 11 h of the cartridge body 10, thus providing a cartridge of a simplified good design.

[0386] As shown in FIG. 66, when closed, the shutters 21 and 62 are not entirely in contact with each other along a line but have a plurality of contact portions that are not aligned with the line. More specifically, the shutters 21 and 22 have a first pair of contact portions 21 f and 22 f over the chucking opening 11 c and a second pair of contact portions 21 g and 22 g over the head opening 11 h, respectively. In this preferred embodiment, the contact portions 21 f and 22 f contact with each other along the centerline of the disc cartridge 313. On the other hand, the contact portions 21 g and 22 g contact with each other along a line that defines a predetermined angle (e.g., approximately 15 degrees to approximately 16 degrees) with the centerline of the disc cartridge 313. When the shutters 21 and 22 have such shapes, the shutter 22 can have an integral shape from the vicinity of the shutter opener/closer 22 t and can exhibit sufficiently high rigidity.

[0387] Shutter springs 31 and 32 are provided outside of the disc storage portion 10 d for the shutters 21 and 22, respectively. These springs 31 and 32 apply an elastic force to the shutters 21 and 22 in such a direction as to close the shutters 21 and 22. The shutter springs 31 and 32 are inserted into two spring poles 11 t on the inner lower surface 11 u of the cartridge body 10. In this preferred embodiment, torsion coil springs are used as the shutter springs 31 and 32. The torsion coil springs 31 and 32 preferably have the same shape to reduce the cost. Examples of other elastic members that may be used as the shutter springs 31 and 32 include compression springs, leaf springs and elastic resin springs.

[0388] As shown in FIG. 65, the disc cartridge 313 includes a write protector 40, which is inserted into a groove 11 v of the lower shell 11 so as to slide along the groove 11 v. By sliding the write protector 40, the convex portion 40 t can be moved, thereby turning ON or OFF a sensor switch provided for a disc drive. In this manner, writing on the disc 100 may be either prohibited or allowed.

[0389] That is to say, this disc cartridge 313 is made up of the cartridge body 10 consisting of the lower and upper shells 11 and 12, disc stoppers 23, shutters 21 and 22, shutter springs 31 and 32, and write protector 40.

[0390] When the lower and upper shells 11 and 12 are joined together, the two shafts 11 s of the lower shell 11 are engaged with two concave portions 12 h of the upper shell 12. In this manner, the shafts 11 s can have their rigidity increased. Thus, even when the shutters 21 and 22 are open, reduced torsion is created at the respective centers of rotation of the shutters 21 and 22 by the elastic force applied from the shutter springs 31 and 32. As a result, the shutters 21 and 22 can be opened to the intended angle.

[0391] As shown in FIG. 64, the upper surface of the cartridge body 10 (or the upper shell 12) has a label plane 10 f, on which the user can note down the contents of the disc 100 stored, and an embossed arrow mark (or concave portion) 10 a that indicates the direction (the arrow 1A) in which this disc cartridge 313 should be inserted into a disc drive.

[0392] The cartridge body 10 further includes two pairs of concave portions 10 c and 10 e on two of its side surfaces that are parallel to the direction 1A in which the disc cartridge 313 is inserted. These concave portions 10 c and 10 e may be used as either pull-in notches or positioning recesses when the disc cartridge 313 is pulled in and loaded into a disc drive or when the disc cartridge 313 is stored in a disc changer. The cartridge body 10 further includes a slit 10 b on one of its side surfaces. The slit 10 b may be used as a recess to identify the upside and downside of the disc cartridge 313 from each other when this disc cartridge 313 is inserted into the disc drive.

[0393] Hereinafter, it will be described with reference to FIGS. 66, 67, 68 and 69 how this disc cartridge 313 operates. FIGS. 66 and 67 are plan views illustrating the disc cartridge 313 in a state where its shutters 21 and 22 are closed and in a state where its shutters 21 and 22 are opened, respectively. FIG. 68 is a plan view illustrating the details of the shutter locking mechanism 20 k. And FIG. 69 is a cross-sectional view illustrating the details of the disc holder 22 a of the shutter 22.

[0394] First, a storage state of the disc cartridge 313, i.e., a state of the disc cartridge 313 that has not been loaded into a disc drive yet, will be described. In that state, the shutters 21 and 22 are closed as shown in FIG. 66. Also, as shown in FIG. 69, the slope 22 a′ of the disc holder 22 a of the shutter 22 contacts with the outer edge of the disc 100, thereby holding the disc 100 thereon and pressing the disc 100 in the thickness direction loot. As a result, the signal recording side 100A of the disc 100 is brought into contact with the sheet 22 p of the shutter 22 and the disc 100 is fixed in the cartridge body 10. The three other disc holders 21 a, 21 b and 22 b also have their own slopes 21 a′, 21 b′ and 22 b′, respectively. Thus, just like the disc holder 22 a, these disc holders 21 a, 21 b and 22 b also hold and fix the disc 100 in the cartridge body 10.

[0395] In this state, the signal recording side 100A of the disc 100 is in close contact with the sheets 21 p and 22 p. Thus, no dust will be deposited on the signal recording side 100A. Also, if the exposed side of the disc 100 is rotated manually or if the shutters 21 and 22 are opened or closed intentionally, then dust, finger marks or any other dirt that has adhered onto the signal recording side 100A of the disc 100 may be wiped away.

[0396] Furthermore, since the shutters 21 and 22 are locked by the locking mechanism 20 k, the user cannot open the shutters 21 and 22 accidentally. Thus, the signal recording side 100A of the disc 100 can be protected from dust, finger marks or scratches.

[0397] Furthermore, the shutters 21 and 22 are provided with notches 21 h and 22 h, respectively. When the shutters 21 and 22 are closed, these notches 21 and 22 contact with each other to form a hole 20 h just under the center hole 100 h of the disc 100. In such a structure, even if this disc cartridge 313 is left with the upper side of the disc 100 exposed upward, dust will pass through the center hole 100 h but will not be deposited on the shutters 21 and 22.

[0398] Also, while the shutters 21 and 22 are closed, at least the two pairs of contact portions 21 f, 22 f and 21 g, 22 g of the shutters 21 and 22, which are butted with each other over the chucking and head openings 11 h and 11 c, respectively, each overlap with each other in the thickness direction of the disc 100 as shown in FIGS. 70 and 71. Accordingly, even if the shutters 21 and 22 have been closed incompletely because a disc 100 having a non-regular diameter has been mounted on this disc cartridge 313 or because the shutters 21 and 22 have not been locked completely, no gap will be created between the contact portions of the shutters 21 and 22. Thus, even in such a situation, the disc 100 can also be protected from dust, finger marks or scratches.

[0399] Also, as shown in FIG. 70, the shutters 21 and 22 are in contact with each other around the head opening 11 h so that the contact portion 22 g of the shutter 22 is located over the contact portion 21 g of the shutter 21. On the other hand, as shown in FIG. 71, the shutters 21 and 22 are in contact with each other around the chucking opening 11 c so that the contact portion 21 f of the shutter 21 is located over the contact portion 22 f of the shutter 22. In this manner, the angle defined by one of multiple contact portions 21 f or 21 g or 22 f or 22 g of the shutter 21 or 22 may be different from the angle defined by another one of the contact portions 21 g or 21 f or 22 g or 22 f of the shutter 21 or 22. In such a structure, the two shutters 21 and 22 can be tightly engaged with each other in the thickness direction of the disc 100. Thus, neither the shutter 21 nor the shutter 22 will be raised unintentionally. In addition, while the shutters 21 and 22 are closed, the contact portions of the shutters 21 and 22 can exhibit increased rigidity.

[0400] In this preferred embodiment, the shutters 21 and 22 have the contact portions 21 f, 21 g, 22 f and 22 g shown in FIGS. 70 and 71. However, the shutters 21 and 22 may also have contact portions at different locations or may contact with each other in a different manner. For example, the contact portions 21 g and 22 g shown in FIG. 70 may be shifted to a location around the head opening 11 h or the contact portions 21 f and 22 f shown in FIG. 71 may be shifted to a location around the chucking opening 11 c. Then, the shutters 21 and 22 can exhibit even higher rigidity when closed, and the gap between the contact portions can be further reduced, thus preventing the dust from entering the inside of the cartridge.

[0401] Also, while the shutters 21 and 22 are closed, convex portions 21 j and 22 j, provided for the shutters 21 and 22 as shown in FIG. 68, are in contact with two shutter stoppers 12 f provided for the upper shell 12 as shown in FIG. 65. Accordingly, the shutters 21 and 22 have its rotation regulated and cannot move from their locked positions. As a result, the shutters 21 and 22 will not move inconstantly in their locked state. In addition, it is possible to prevent the user from breaking the shutters 21 and 22 intentionally. Furthermore, since the shutters 21 and 22 have their rotation regulated, the shutter opener/closer 22 t is not displaced. Accordingly, when this disc cartridge 313 is loaded into a disc drive, the shutter opener/closer 22 t can be engaged with the shutter opening/closing mechanism of the disc drive just as intended.

[0402] Hereinafter, it will be described how this disc cartridge 313 is loaded into the disc drive. As shown in FIG. 66, when the disc cartridge 313 is inserted into the disc drive in the direction 1A, the cartridge positioning pins of the disc drive engage with the positioning holes 11 w of the disc cartridge 313, thereby determining the horizontal and vertical positions of the disc cartridge 313 inside the disc drive.

[0403] Next, a shutter opener/closer of the shutter opening/closing mechanism provided inside the disc drive engages with the shutter opener/closer 22 t shown in FIG. 68. At the same time, an unlocking member of the shutter opening/closing mechanism presses an unlocking portion 21 y, which is connected to the shutter 21 by way of an elastic portion 21 e, in the direction 20A. As a result, the locking protrusion 21 k of the locking mechanism 20 k is disengaged from the locking engaging portion 22 k thereof, thereby unlocking the shutters 21 and 22 from each other. In such a state, the shutter opener/closer of the shutter opening/closing mechanism moves the shutter opener/closer 22 t in the direction indicated by the arrow 20B. Consequently, the shutter 21 rotates on the shaft 11 s while dominating the elastic force applied from the shutter spring 31 as shown in FIG. 67. Synchronously with the movement of the shutter 21, the other shutter 22, which is interlocked with the former shutter 21 via the interlocking mechanism 20 c, also rotates while dominating the elastic force applied from the shutter spring 32. Accordingly, when the shutter 21 has been opened, the shutter 22 will have also been opened.

[0404] By the time the shutters 21 and 22 are opened completely, the locking protrusion 21 k and the unlocking portion 21 y will have returned to their home positions along with the elastic portion 21 e. Thus, the elastic portion 21 e made of a resin is not deformed plastically. In this manner, the signal recording side 100A of the disc 100 is exposed through the chucking and head openings 11 c and 11 h. Also, the disc 100, which has been held by the disc holders 21 a, 21 b, 22 a and 22 b, is released therefrom as the shutters 21 and 22 rotate. As a result, the disc 100 is now freely rotatable inside the disc storage portion 10 d.

[0405] Subsequently, the spindle motor and the turntable of the disc drive enter the chucking opening 11 c and the head of the disc drive enters the head opening 11 h. Consequently, the disc drive is now ready to perform a read or write operation on the disc 100 loaded.

[0406] As described above, only by getting the locking protrusion 21 k pressed externally by a protrusion, for example, in the direction indicated by the arrow 20A and disengaged from the locking engaging portion 22 k while pressing the shutter opener/closer 22 t in the direction indicated by the arrow 20B at the same time, the shutters 21 and 22 can be rotated to expose the chucking and head openings 11 c and 11 h and the disc 100 can be released from the disc holders 21 a, 21 b, 22 a and 22 b. Thus, it is possible to prevent the user from opening the shutters 21 and 22 or removing the disc 100 accidentally. As a result, the disc 100 can be protected from dust, finger marks or scratches.

[0407] Hereinafter, it will be described how the disc cartridge 313 is ejected from the disc drive. When an ejecting mechanism of the disc drive starts to operate, the shutter opener/closer of the disc drive, which has been engaged with the shutter opener/closer 22 t, disengages itself from the shutter opener/closer 22 t. As a result, the shutters 21 and 22 cannot be kept opened and start to rotate in the opposite direction. That is to say, the shutters 21 and 22, to which an elastic force is being applied from the shutter springs 31 and 32 in such a direction as to close the shutters 21 and 22, start to close themselves. Consequently, the shutters 21 and 22 close up the head and chucking openings 11 h and 11 c. In this case, the shutters 21 and 22 are locked to each other by the locking mechanism 20 k. In the meantime, the disc 100 gets held by the disc holders 21 a, 21 b, 22 a and 22 b again to recover its original state. Then, the disc cartridge 313 is ejected from the disc drive.

[0408] In the disc cartridge 313, the disc contact portion 23 a of the disc stoppers 23 provided for the cartridge body 10 and the disc contact portion 12 s′ of the upper shell 12 are located at the same vertical level as shown in FIG. 69. Also, the top of the slopes 21 a′, 21 b′, 22 a′ and 22 b′ of the disc holders 21 a, 21 b, 22 a and 22 b of the shutters 21 and 22 is higher in level than the bottom of the disc contact portions 23 a and 12 s′ in the direction 100 u in which the disc 100 is movable. Accordingly, even if the disc cartridge 313 is loaded into a disc drive either vertically or upside down, the shutters 21 and 22 still can hold the disc 100 firmly thereon. For example, if the disc cartridge 313 is loaded upside down into a disc drive, the disc 100 that is no longer chucked contacts with the disc contact portions 23 a and 12 s′ and still can maintain its horizontal position. And when the shutters 21 and 22 are closed in such a state, the disc 100 contacts with the slopes 21 a′, 21 b′, 22 a′ and 22 b′ this time. Then, the disc 100 will slide along the slopes 21 a′, 21 b′, 22 a′ and 22 b′ smoothly to be held firmly by the disc holders 21 a, 21 b, 22 a and 22 b.

[0409] In the disc cartridge of the thirteenth preferred embodiment described above, the cartridge body thereof has a disc window and covers only one side of the disc. Also, the disc cartridge includes a shutter opener/closer inside a head opening of the cartridge body, and therefore, there is no need to provide an unnecessary gap for the cartridge body. As a result, no dust will enter the inside of the cartridge body.

[0410] In addition, in the disc cartridge of this thirteenth preferred embodiment, the two shutters thereof are made to contact with each other along the centerline of the disc over the chucking opening and along a line, which defines a predetermined angle with the centerline, over the head opening. Accordingly, these shutters can have an integrated structure from the vicinity of the shutter opener/closer and can exhibit sufficiently high rigidity.

[0411] Furthermore, since the two shutters are locked or unlocked to/from each other, the user cannot open or close the shutters accidentally. Thus, the disc can be protected from dust, finger marks or scratches.

[0412] Moreover, at least one of multiple disc holders of the disc cartridge is not secured to its associated shutter but is just connected thereto via an elastic portion. As an elastic force is also applied from a shutter spring to that disc holder, the disc holder can be deformed sufficiently elastically in the disc radial direction. For that reason, even if a disc of a non-regular size has been mounted on this disc cartridge, the disc cartridge can also hold such a disc firmly without allowing it to move inconstantly.

[0413] Embodiment 14

[0414] Hereinafter, a disc cartridge 314 according to a fourteenth specific preferred embodiment of the present invention will be described with reference to FIGS. 72 through 81. In FIGS. 72 through 81, each member of the disc cartridge 314 of the fourteenth preferred embodiment, having substantially the same function as the counterpart of the disc cartridge 313 of the thirteenth preferred embodiment described above, is identified by the same reference numeral.

[0415] The disc cartridge 314 of the fourteenth preferred embodiment is different from the disc cartridge 313 of the thirteenth preferred embodiment described above in the respective shapes of the inner upper surface 12 u of the cartridge body 10 (see FIG. 79), the disc holders 21 a, 21 b, 22 a and 22 b (see FIGS. 72 through 79) and the disc stoppers 53 (see FIGS. 72, 77 and 78). In addition, the disc cartridge 314 further includes a disc supporting portion 60 (see FIGS. 72 and 81). Thus, the following description of the disc cartridge 314 of the fourteenth preferred embodiment of the present invention will be focused on these differences.

[0416] In the disc cartridge 313 of the thirteenth preferred embodiment described above, the respective tops of the disc holders 21 a, 21 b, 22 a and 22 b thereof are located at substantially the same vertical levels along the outer periphery of the disc 100. In contrast, in the disc cartridge 314 of this fourteenth preferred embodiment, protrusions are formed on predetermined areas of the disc holders 21 b, 22 a and 22 b as shown in FIGS. 73 and 79. More specifically, as shown in FIG. 79, each of these three disc holders 21 b, 22 a and 22 b includes: a first portion 121 b, 122 a or 122 b that has a protrusion thereon and has a first height h1 as measured from the upper surface of the shutters 21 and 22; and a second portion 221 b, 222 a or 222 b that has a second height h2 as measured from the upper surface of the shutters 21 and 22. The other disc holder 21 a consists of a second portion 221 a that has the second height h2.

[0417] The first height h1 is greater than the second height h2 and is approximately equal to the height (i.e., the vertical level of the upper surface) of the disc holders 21 a, 21 b, 22 a and 22 b of the disc cartridge 313 of the thirteenth preferred embodiment described above. That is to say, the disc holders 21 a, 21 b, 22 a and 22 b of this fourteenth preferred embodiment are lower than the counterparts of the disc cartridge 313 of the thirteenth preferred embodiment except their first portions 121 b, 122 a and 122 b.

[0418] Also, as shown in FIGS. 74 and 75, a stepped protrusion 223 is formed on the upper surface of the first portion 122 a of the disc holder 22 a. The stepped protrusion 223 has two vertical levels, the higher one of which is closer to the disc 100 mounted. A similar stepped protrusion is also formed on the upper surface of the first portion 121 b of the disc holder 21 b and on the upper surface of the first portion 122 b of the disc holder 22 b.

[0419] As the shutter 21 or 22 is getting closed, the first portion 121 b, 122 a or 122 b of the disc holder 21 b, 22 a or 22 b contacts with the disc 100 earlier than any other portion thereof (i.e., earlier than the second portion 221 b, 222 a or 222 b thereof).

[0420] The disc holders 21 a, 21 b, 22 a and 22 b move as the shutters 21 and 22 are opened or closed. FIG. 77 illustrates the respective positions of the disc holders 21 a, 21 b, 22 a and 22 b while the shutters 21 and 22 are closed. On the other hand, FIG. 78 illustrates the respective positions of the disc holders 21 a, 21 b, 22 a and 22 b while the shutters 21 and 22 are opened. FIGS. 79 and 80 are cross-sectional views illustrating portions of the disc cartridge 314 that are respectively viewed along the lines B-B and C-C shown in FIG. 78.

[0421] As shown in FIGS. 77, 78 and 79, the regions 12 y, 12 x and 12 z on the inner upper surface 12 u of the cartridge body 10, through which the first portions 121 b, 122 a and 122 b of the disc holders 21 b, 22 a and 22 b pass as the shutters 21 and 22 are opened or closed, are recessed. On the other hand, the regions 12 y′, 12 x′ and 12 z′, through which the second portions 221 b, 222 a and 222 b thereof pass, are not recessed. Accordingly, the upper shell 12 is thinner in the regions 12 x, 12 y and 12 z than in the regions 12 x′, 12 y′ and 12 z′.

[0422] As shown in FIGS. 76 and 79, the top of the first portion 122 a of the disc holder 22 a is located at a vertical level higher than the bottom of the disc stopper 53. Also, the top of the first portion 122 a of the disc holder 22 a is received by the recessed first region 12 x on the inner upper surface 12 u. Since the stepped protrusion 223 is formed at the top of the first portion 122 a, just a part of the upper surface of the first portion 122 a is in contact with the inner upper surface 12 u. On the other hand, the second portion 222 a of the disc holder 22 a is not in contact with the inner upper surface 12 u.

[0423] To open and close the shutters 21 and 22 smoothly, the friction caused by the contact between the top of the first portion 122 a of the disc holder 22 a and the inner upper surface 12 u is preferably small. For that purpose, the top of the first portion 122 a of the disc holder 22 a has an arc-shaped cross section when taken in the radial direction of the disc 100. This stepped protrusion 223 is provided to compensate for shortage in mechanical strength, which would be caused by a sharpened top of the first portion 122 a, and to make that top moldable more accurately and more easily.

[0424] As shown in FIG. 80, the top of the first portion 122 b of the disc holder 22 b is also located at a vertical level higher than the bottom of the disc stopper 53. And the top of the first portion 122 b of the disc holder 22 b is received by the recessed first region 12 z on the inner upper surface 12 u. Although not shown, the top of the first portion 121 b of the disc holder 21 b is also located at a vertical level higher than the bottom of the disc stopper 53, and is received by the recessed first region 12 y on the inner upper surface 12 u.

[0425] As described above, in the disc cartridge 314 of the fourteenth preferred embodiment, the regions 12 x, 12 y and 12 z on the inner upper surface 12 u are recessed to receive portions of the disc holders 22 a, 21 b and 22 b, respectively. Thus, the thickness of the disc cartridge 314 can be reduced by the depth of those recessed regions 12 x, 12 y and 12 z.

[0426] Even if the disc cartridge 314 having such a structure is loaded into a disc drive either vertically or upside down, the disc 100 that is no longer chucked never fails to contact with the slope 122 a′ of the first portion 122 a of the disc holder 22 a as shown in FIG. 79 as the shutters 21 and 22 are closed. Thereafter, the disc 100 will slide smoothly along the slope 122 a′ to contact with the slope 222 a′ of the second portion 222 a of the disc holder 22 a (see FIG. 74). At the same time, the disc 100 also contacts with the slope 221 a′ of the second portion 221 a of the disc holder 21 a. In this manner, the disc holders 21 a and 22 a hold the disc 100 thereon cooperatively. The two other disc holders 21 b and 22 b also hold the disc 100 thereon through similar operations. Accordingly, although this disc cartridge 314 has a reduced thickness, the disc cartridge 314 can close the shutters 21 and 22 in any position and can hold the disc 100 thereon just as intended.

[0427] If this disc cartridge had its thickness just reduced without changing the shapes of the disc holders (or using the disc holders of the thirteenth preferred embodiments as they are), the regions 12 x, 12 x′, 12 y, 12 y′, 12 z and 12 z′ on the inner upper surface 12 u, through which the disc holders 22 a, 21 b and 22 a pass, should all be recessed as can be seen from FIG. 78. In that case, the upper shell 12 would have a reduced thickness over a rather wide area and such a disc cartridge would have a decreased mechanical strength. In contrast, the disc cartridge 314 of this fourteenth preferred embodiment can have its thickness reduced without decreasing its mechanical strength because the regions 12 x, 12 y and 12 z with a reduced thickness are relatively narrow.

[0428] In the preferred embodiment described above, three protrusions are provided for three of the four disc holders. However, the number of protrusions to be provided is changeable with the number of disc holders or the shapes of the shutters.

[0429] The disc cartridge 314 of the fourteenth preferred embodiment is also different from the disc cartridge 313 of the thirteenth preferred embodiment in the shape of the disc stoppers 53.

[0430] As shown in FIG. 72, the disc stoppers 53 have the shape of a notched circular plate. Specifically, notches 54 having substantially the same shape as the disc stoppers 53 are provided along the disc window 12 w of the upper shell 12 and the disc stoppers 53 are engaged in a rotatable state with the notches 54. As shown in FIG. 77, the disc stoppers 53 are held in such a manner as to partially protrude into the disc window 12 w of the upper shell 12 when rotated. Also, as shown in FIG. 78, by rotating the disc stoppers 53, the disc stoppers 53 may also be held in such a manner as to be stored inside the upper shell 12 and not to protrude into the disc window 12 w. If the disc stoppers 53 are easily disengaged from the notches 54 unintentionally, then the side surfaces of the disc stoppers 53 and the notches 54 of the upper shell 12 may have mutually engaging concave and convex portions, for example.

[0431] In such a structure, the thickness of the disc stoppers 53 may be substantially equal to that of the upper part of the upper shell 12. Thus, the disc cartridge 314 can have a reduced overall thickness.

[0432] The disc cartridge 314 of this fourteenth preferred embodiment is also characterized by including a disc supporting portion 60 at the bottom of the inner periphery of the disc storage portion. The disc supporting portion 60 is located between the inner lower surface 11 u and the inner side surface 11 i of the cartridge body 10 as shown in FIGS. 72, 77, 78 and 81. As shown in FIG. 81, the disc supporting portion 60 has an upper surface 60 a, which is parallel to the inner lower surface 11 u of the cartridge body 10.

[0433] As also shown in FIG. 81, while the shutters 21 and 22 are closed and the disc 100 is held by the disc holders, the outer edge and its surrounding portion of the signal recording side 100A of the disc 100 are in contact with the upper surface 60 a of the disc supporting portion 60. Thus, no dust will be deposited on the signal recording side 100A of the disc 100 or accumulated on the inner lower surface 11 u of the cartridge body 10.

[0434] Alternatively, the disc supporting portion 60 may have any shape other than that shown in FIG. 81. For example, as shown in FIG. 82, a disc supporting portion 76 having an upwardly tapered cross section may be formed between the inner lower surface 11 u and the inner side surface 11 i of the cartridge body 10. In that case, while the shutters 21 and 22 are closed and the disc 100 is held by the disc holders, the outer edge of the signal recording side 100A of the disc 100 is in contact with the disc supporting portion 76.

[0435] Embodiment 15

[0436] Hereinafter, a disc cartridge 315 according to a fifteenth specific preferred embodiment of the present invention will be described with reference to FIGS. 83 through 87. In FIGS. 83 through 87, each member of the disc cartridge 315 of the fifteenth preferred embodiment, having substantially the same function as the counterpart of the disc cartridge 314 of the fourteenth preferred embodiment described above, is identified by the same reference numeral.

[0437] As shown in FIG. 83, unlike the disc cartridge 314 of the fourteenth preferred embodiment described above, the disc cartridge 315 of this fifteenth preferred embodiment includes four types of recesses 85, 86, 87 and 88 a through 88 c. The recesses 85 are formed on the respective lower surfaces 21 v and 22 v of the shutters 21 and 22. The other three types of recesses 86, 87 and 88 a through 88 c are formed on the inner lower surface 11 u of the cartridge body 10 that contacts with the shutters 21 and 22. These four types of recesses will be described below one by one. Where the disc cartridge 315 is supposed to hold a disc having a diameter of about 12 cm, these recesses may have a depth of about 0.1 mm to about 0.3 mm, for example.

[0438] As can be seen from FIGS. 84 and 85 illustrating two states of the disc cartridge 315 in which its shutters 21 and 22 are closed and opened, respectively, the first type of recesses 86 are formed in respective regions of the inner lower surface 11 u that contact with the disc holders 21 a, 21 b, 22 a and 22 b of the shutters 21 and 22 when the shutters 21 and 22 are opened or closed.

[0439] The disc holders 21 a, 21 b, 22 a and 22 b are sandwiched between the upper and lower shells 12 and 11 with almost no gap left between them. Accordingly, when respective members of the disc cartridge 315 are assembled together or if any of those members of the disc cartridge 315 has a size that is greatly different from the designed one, the disc holders 21 a, 21 b, 22 a and 22 b might contact with the upper and lower shells 12 and 11. In that case, excessive friction would be created between the disc holders 21 a, 21 b, 22 a and 22 b and the upper or lower shell 12 or 11. As a result, the shutters 21 and 22 might be unable to be opened or closed so easily or dust might be stirred up due to the excessive friction.

[0440] However, by providing the first type of recesses 86, gaps are provided under the disc holders 21 a, 21 b, 22 a and 22 b, thus reducing such unwanted friction. Then, the shutters 21 and 22 can always be opened or closed smoothly and no dust will be stirred up due to the friction.

[0441] The second type of recesses 87 are formed in those regions of the inner lower surface 11 u where the respective outer edges of the shutters 21 and 22 are located while the shutters 21 and 22 are closed. As shown in FIGS. 84 and 86, these recesses 87 preferably extend along the boundary that defines the outer edges of the shutters 21 and 22 on the inner lower surface 11 u and are preferably present both inside and outside of the boundary.

[0442] This disc cartridge 315 is supposed to store the disc 100 therein with one side thereof exposed, and the user can press the disc 100 in the direction indicated by the arrow A in FIG. 86. To protect the signal recording side 100A of the disc 100, the respective upper surfaces of the shutters 21 and 22 are covered with the nonwoven fabrics 21 s and 22 s but their outer edges are not completely covered with the nonwoven fabrics 21 s and 22 s. Accordingly, if the disc 100 is pressed in the direction A, then the outer edges of the shutters 21 and 22 contact with the signal recording side 100A of the disc 100, thus possibly scratching the signal recording side 100A as shown in FIG. 86.

[0443] However, if the second type of recesses 87 are provided, the shutters 21 and 22 may be deformed in such a manner that the outer edges thereof are partially forced into the second type of recesses 87. Then, the pressing force can be dispersed, and the outer edges of the shutters 21 and 22 will not be pressed against the signal recording side 100A of the disc 100 too strongly.

[0444] The third type of recesses include: recesses 88 a that are formed on the inner lower surface 11 u so as to surround the chucking and head openings 11 c and 11 h; recesses 88 b that are formed in those regions of the inner lower surface 11 u that are not overlapped by the shutters 21 and 22 when the shutters 21 and 22 are closed; and a recess 88 c that is located in a region of the inner lower surface 11 u that is overlapped by the shutters 21 and 22 when the shutters 21 and 22 are closed. The recesses 88 b and 88 c are provided so as to draw a circle along the circumference of the disc storage portion 10 d. In this preferred embodiment, the number of the recesses 88 a of the third type is three.

[0445] This disc cartridge 315 is also provided with various types of structures (e.g., a disc supporting portion) for preventing dust from entering the disc cartridge 315 or being deposited on the signal recording side 100A of the disc 100. However, it is actually difficult to totally eliminate the dust that enters the disc cartridge 315 or is deposited on the signal recording side 100A.

[0446] Thus, the third type of recesses 88 a, 88 b and 88 c are provided to accumulate the dust that has entered the disc cartridge 315. Specifically, as the shutters 21 and 22 are opened or closed, the dust is collected in these recesses 88 a, 88 b and 88 c of the third type. Once collected in the recesses 88 a, 88 b and 88 c, the dust never contacts with the shutters 21 and 22 and remains in the recesses 88 a, 88 b and 88 c without going out of the recesses 88 a, 88 b and 88 c. Accordingly, by accumulating the dust in the third type of recesses 88 a, 88 b and 88 c in this manner, the dust will not interfere with opening or closing of the shutters 21 and 22 or will be stirred up due to an excessive friction.

[0447] It should be noted that these effects are also achievable by the first type of recesses 86 or the second type of recesses 87. Accordingly, the disc cartridge 315 does not have to include all of these recesses 86, 87, 88 a, 88 b and 88 c but may include just one type of recesses. Even so, the shutters 21 and 22 will not be interfered with their opening or closing by the dust and almost no dust will be stirred up due to a friction.

[0448] Also, to remove the dust from the gap between the shutters 21 and 22 and the inner lower surface 11 u and accumulate it in the second type of recesses 87, for example, even more effectively, the respective lower surfaces 21 v and 22 v of the shutters 21 and 22 may be provided with the recesses 85 along the outer edges thereof. In that case, when the shutters 21 and 22 are closed, these recesses 85 are preferably located inside the second type of recesses 87 (i.e., closer to the centerline of the cartridge 315) as shown in FIG. 84. Also, as shown in FIG. 86, when the shutters 21 and 22 are closed, the recesses 85 of the shutters 21 and 22 are preferably discontinuous with the second type of recesses 87 on the inner lower surface 11 u.

[0449] When the shutters 21 and 22 have the recesses 85, the outer edges of the shutters 21 and 22 are deformed more easily. Accordingly, even when a force is externally applied to the disc 100 in the direction A, the outer edges of the shutters 21 and 22 are deformed easily and will much less likely press the signal recording side 100A of the disc 100 so strongly as to scratch it. Optionally, these recesses 86, 87, 88 a, 88 b and 88 c may have their inner faces covered with a nonwoven fabric that has been adhered or welded thereto. Then, the gaps created by these recesses inside the cartridge body can be filled and dust will enter this disc cartridge 315 even less easily.

[0450] In the fifteenth preferred embodiment described above, the various types of recesses are provided for the disc cartridge 314 of the fourteenth preferred embodiment. Alternatively, these recesses may also be provided for the disc cartridge according to any of the eighth through thirteenth preferred embodiments of the present invention described above.

[0451] Embodiment 16

[0452] Hereinafter, a disc cartridge 316 according to a sixteenth specific preferred embodiment of the present invention will be described with reference to FIGS. 88 through 93. In FIGS. 88 through 93, each member of the disc cartridge 316 of the sixteenth preferred embodiment, having substantially the same function as the counterpart of the disc cartridge 313 of the thirteenth preferred embodiment described above, is identified by the same reference numeral.

[0453] As shown in FIG. 88, the disc cartridge 316 of this preferred embodiment includes first and second opener/closers 22 t and 93 on first and second side surfaces 10 p and 10 q of the cartridge body 10, respectively. The first opener/closer 22 t is formed on the first side surface lop that extends substantially vertically to the direction 1A in which this disc cartridge 316 is inserted into a disc drive, while the second opener/closer 93 is formed on the second side surface 10 q that extends substantially parallelly to the direction 1A. The first opener/closer 22 t has the same structure as the shutter opener/closer 22 t of the disc cartridge 313 of the thirteenth preferred embodiment.

[0454] As shown in FIG. 89, the second opener/closer 93 is formed in the shape of a gear having a hole that can be inserted into a shaft 11 q provided for the lower shell 11. A side surface of the lower shell 11 has an opening 11 r to expose a portion of the second opener/closer 93 through the second side surface 10 q of the cartridge body 10 when the second opener/closer 93 is inserted into the shaft 11 q. Alternatively, the shaft 11 q may be provided for the upper shell 12.

[0455] The shutters 21 and 22 are also provided to expose or cover the head and chucking openings 11 h and 11 c of the lower shell 11. The shutters 21 and 22 are equivalent to the second and first shutters as defined in the appended claims. The first opener/closer 22 t forms an integral part of the shutter 22. On the other hand, a sector gear 21 m, which engages with the second opener/closer 93, is formed on the outer side surface of the shutter 21 and is located near the disc holder 21 b. The center of rotation of the sector gear 21 m is the shaft hole 21 u of the shutter 21. The outer side surface of the shutter 21 also has a concave portion 21 n, which is adjacent to the sector gear 21 m. This concave portion 21 n is formed to define a space in which the second opener/closer 93 engages with the sector gear 21 m.

[0456] The shutters 21 and 22 may be opened or closed by using the first opener/closer 22 t in the following manner. First, as shown in FIG. 90, the locking protrusion 21 k and the locking engaging portion 22 k, which together make up the locking mechanism 20 k, are disengaged from each other. Then, the first opener/closer 22 t is slid along the first side surface lop of the cartridge body 10 as indicated by the arrow 22W in FIG. 90. As a result, the other shutter 21 is also moved synchronously with the shutter 22 by way of the interlocking mechanism 20 c, and these two shutters 21 and 22 expose the head and chucking openings 11 h and 11 c as shown in FIG. 91.

[0457] The shutters 21 and 22 may also be opened by using the second opener/closer 93 in the following manner. First, the locking mechanism 20 k is unlocked as shown in FIG. 90. Next, the second opener/closer 93 is rotated to the direction indicated by the arrow 93A. Then, the sector gear 21 m gets engaged with the second opener/closer 93 and starts to rotate on the shaft hole 21 u, thereby opening the shutter 21. Since the other shutter 22 is also moved synchronously with the shutter 21 by way of the interlocking mechanism 20 c, these two shutters 21 and 22 expose the head and chucking openings 11 h and 11 c. When the head and chucking openings 11 h and 11 c are completely exposed by the shutters 21 and 22 as shown in FIG. 91, a portion of the second opener/closer 93 is located inside the concave portion 21 n of the shutter 21.

[0458] To close the shutters 21 and 22, the first opener/closer 22 t may be slid in the direction opposite to the direction 22W or the second opener/closer 93 may be rotated to the direction opposite to the direction 93A. In this preferred embodiment, the disc cartridge 316 includes the shutter springs 31 and 32 that apply an elastic force to the shutters 21 and 22 in such a direction as to close the shutters 21 and 22. Accordingly, unless a force that is strong enough to open, or keep opened, the shutters 21 and 22 against the elastic force of the shutter springs 31 and 32 is applied to the first or second opener/closer 22 t or 93, the shutters 21 and 22 close themselves automatically.

[0459] In the disc cartridge 316 of the sixteenth preferred embodiment, the opener/closers are provided for the shutters 21 and 22 both on a side surface that is perpendicular to the direction in which this disc cartridge 316 is inserted into a disc drive and on a side surface that is parallel to the disc cartridge inserting direction. Accordingly, no matter whether the disc drive used is compatible with only a disc cartridge including a shutter opener/closer on a side surface that extends perpendicularly to the disc cartridge inserting direction or only a disc cartridge including a shutter opener/closer on a side surface that extends parallelly to the disc cartridge inserting direction, the disc drive can always read or write a signal from/on the disc stored in the disc cartridge of this preferred embodiment.

[0460] Also, in the disc cartridge 316 of this sixteenth preferred embodiment, the second opener/closer 93, provided for the side surface parallel to the direction in which the disc cartridge 316 is inserted, has a gear shape. Accordingly, a shutter opening/closing mechanism to be provided for the disc drive may also be any of various shapes of gears that can engage with the second opener/closer 93. Thus, the disc drive may use a relatively simple mechanism to open or close the shutters 21 and 22 of the disc cartridge 316.

[0461] In the preferred embodiment described above, the sector gear 21 m is provided near the disc holder 21 b. This is because the distance between the sector gear 21 m at such a position and the shaft hole 21 u of the shutter 21 is relatively short and because the sector gear 21 m needs to have a relatively short length to open the shutter 21 fully. However, the sector gear 21 m does not have to be provided at this position. Alternatively, the sector gear 21 m and the second opener/closer 93 may also be provided at such positions as shown in FIGS. 92 and 93. In the alternative preferred embodiment shown in FIGS. 92 and 93, the sector gear 21 m may be located at such a position that when extended, a circular trace drawn by the sector gear 21 m will substantially intersect with the center of the disc 100, while the second opener/closer 93 may be provided at such a position as to engage with the sector gear 21 m. When the second opener/closer 93 is provided at such a position, the sector gear 21 m should be relatively long to open the shutter 21 fully, but the distance between the sector gear 21 m and the shaft hole 21 u may also be relatively long. That is to say, since there is a long distance between the fulcrum and the application point in that case, a lighter force is needed to rotate the second opener/closer 93 and open or close the shutters 21 and 22.

[0462] Embodiment 17

[0463] Hereinafter, a disc cartridge 317 according to a seventeenth specific preferred embodiment of the present invention will be described with reference to FIGS. 94 through 97. In FIGS. 94 through 97, each member of the disc cartridge 317 of the seventeenth preferred embodiment, having substantially the same function as the counterpart of the disc cartridge 316 of the sixteenth preferred embodiment described above, is identified by the same reference numeral.

[0464] As shown in FIG. 94, the disc cartridge 317 of this seventeenth preferred embodiment includes a second opener/closer 94 on its second side surface 10 q instead of the second opener/closer 93 of the disc cartridge 316 of the sixteenth preferred embodiment described above.

[0465] As can be seen from FIG. 95, the second opener/closer 94 is a link member that can slide along the opening 11 r of the lower shell 11 and that is bent approximately at the center thereof. Also, the second opener/closer 94 includes a protrusion 94 a at one end thereof. This protrusion 94 a engages with a groove 21 i that is provided on the upper surface of the shutter 21 near the disc holder 21 b.

[0466]FIGS. 96 and 97 illustrate two states of the disc cartridge 317 in which the shutters 21 and 22 thereof are closed and opened, respectively. As already described for the thirteenth and sixteenth preferred embodiments, the shutters 21 and 22 can be opened or closed by sliding the first opener/closer 22 t in the direction 22 w or in the opposite direction.

[0467] The shutters 21 and 22 may also be opened by using the second opener/closer 94 in the following manner. First, the locking mechanism 20 k is unlocked as shown in FIG. 96. Next, the second opener/closer 94 is slid in the direction indicated by the arrow 94B. As a result of this operation, a force is applied to the second opener/closer 94 in such a direction as to move the protrusion 94 a of the second opener/closer 94 in the direction indicated by the arrow 94B. Thus, the shutter 21 is rotated on the shaft hole 21 u and opened. Since the other shutter 22 is also moved synchronously with the shutter 21 by way of the interlocking mechanism 20 c, these two shutters 21 and 22 expose the head and chucking openings 11 h and 11 c. As in the sixteenth preferred embodiment described above, the shutters 21 and 22 can also be closed by sliding the second opener/closer 94 in the direction opposite to the direction 94B, and the shutter springs 31 and 32 also apply an elastic force to the shutters 21 and 22 in such a direction as to close the shutters 21 and 22.

[0468] Just like the disc cartridge 316 of the sixteenth preferred embodiment described above, no matter whether the disc drive used is compatible with only a disc cartridge including a shutter opener/closer on a side surface that extends perpendicularly to the disc cartridge inserting direction or only a disc cartridge including a shutter opener/closer on a side surface that extends parallelly to the disc cartridge inserting direction, the disc drive can always read or write a signal from/on the disc stored in the disc cartridge 317 of this preferred embodiment.

[0469] Also, as shown in FIGS. 96 and 97, the direction 94B in which the second opener/closer 94 is slid to open the shutters 21 and 22 is antiparallel to the disc cartridge inserting direction 1A. Accordingly, if a protrusion that engages with the second opener/closer 94 is provided for a disc drive, that protrusion engages with the second opener/closer 94 and opens the shutters 21 and 22 of the disc cartridge 317 while this disc cartridge 317 is going to be inserted into the disc drive. Thus, a simplified shutter opening/closing mechanism may be provided for the disc drive.

[0470] Embodiment 18

[0471] Hereinafter, a disc cartridge 318 according to an eighteenth specific preferred embodiment of the present invention will be described with reference to FIGS. 98 through 101. In FIGS. 98 through 101, each member of the disc cartridge 318 of the eighteenth preferred embodiment, having substantially the same function as the counterpart of the disc cartridge 316 of the sixteenth preferred embodiment described above, is identified by the same reference numeral.

[0472] As shown in FIG. 98, the disc cartridge 318 of this eighteenth preferred embodiment includes a second opener/closer 96 on its second side surface 10 q instead of the second opener/closer 93 of the disc cartridge 316 of the sixteenth preferred embodiment described above.

[0473] As can be seen from FIG. 99, the second opener/closer 96 is a belt member that is connected to the disc holder 21 a of the shutter 21. This belt member 96 has a protrusion 96 a at one end thereof. And the protrusion 96 a can slide along the opening 11 r of the lower shell 11. Alternatively, the second opener/closer 96 may form an integral part of the shutter 21.

[0474]FIGS. 100 and 101 illustrate two states of the disc cartridge 318 in which the shutters 21 and 22 thereof are closed and opened, respectively. As already described for the sixteenth and seventeenth preferred embodiments, the shutters 21 and 22 can be opened or closed by sliding the first opener/closer 22 t in the direction 22 w or in the opposite direction.

[0475] The shutters 21 and 22 may also be opened by using the second opener/closer 96 in the following manner. First, the locking mechanism 20 k is unlocked as shown in FIG. 100. Next, the protrusion 96 a of the second opener/closer 96 is slid in the direction indicated by the arrow 96B. As a result of this operation, a force is applied to the shutter 21 in such a direction as to rotate the end of the shutter 21 on the shaft hole 21 u, i.e., to the direction indicated by the arrow 96C. Since the other shutter 22 is also moved synchronously with the shutter 21 by way of the interlocking mechanism 20 c, these two shutters 21 and 22 expose the head and chucking openings 11 h and 11 c. To close the shutters 21 and 22, the protrusion 96 a of the second opener/closer 96 may be slid in the opposite direction.

[0476] Just like the disc cartridge 316 of the sixteenth preferred embodiment described above, no matter whether the disc drive used is compatible with only a disc cartridge including a shutter opener/closer on a side surface that extends perpendicularly to the disc cartridge inserting direction or only a disc cartridge including a shutter opener/closer on a side surface that extends parallelly to the disc cartridge inserting direction, the disc drive can always read or write a signal from/on the disc stored in the disc cartridge 318 of this preferred embodiment.

[0477] If the second opener/closer 96 forms an integral part of the shutter 21, the number of members that make up the disc cartridge 318 can be reduced. As a result, the disc cartridge can be manufactured at a lower cost or the manufacturing process thereof can be simplified.

[0478] In the sixteenth through eighteenth preferred embodiments of the present invention described above, the second opener/closer is provided on the left-hand side with respect to the disc cartridge inserting direction. However, the location of the second opener/closer is not limited to the left-hand side. Alternatively, the second opener/closer may be provided on the right-hand side 10 r of the disc cartridge 316 with respect to the disc cartridge inserting direction as shown in FIG. 88. As another alternative, the second opener/closer may also be provided on the backside 10 t of the disc cartridge 316 as shown in FIG. 88. In that case, the belt-shaped second opener/closer 96 of this eighteenth preferred embodiment is preferably used because the disc cartridge 318 can have the protrusion 96 a of the second opener/closer 96 on its backside without changing its details so much.

[0479] Embodiment 19

[0480] Hereinafter, a disc cartridge 319 according to a nineteenth specific preferred embodiment of the present invention will be described with reference to FIGS. 102 and 103. In FIGS. 102 through 103, each member of the disc cartridge 319 of the nineteenth preferred embodiment, having substantially the same function as the counterpart of the disc cartridge 313 of the thirteenth preferred embodiment described above, is identified by the same reference numeral.

[0481] The disc cartridge 319 of this preferred embodiment is characterized by providing rotation stoppers 97 for the disc holders 21 b, 22 a and 22 b and concave portions 89 for the shutters 21 and 22, respectively. The concave portions 89 are used to ultrasonic weld a nonwoven fabric to the shutters 21 and 22.

[0482] More specifically, the disc holders 21 b, 22 a and 22 b include holes 21 q, 22 r and 22 q that engage with the rotation stoppers 97. As shown in FIG. 103, the rotation stoppers 97 partially protrude from the slopes 21 b′, 22 a′ and 22 b′ of the disc holders 21 b, 22 a and 22 b and contact with the outer edge of the disc 100 while the disc 100 is held by the disc holders 21 a, 21 b, 22 a and 22 b. The rotation stoppers 97 are preferably made of an elastic material that has a large coefficient of friction, e.g., rubber.

[0483] It should be noted that at least one of the disc holders 21 a, 21 b, 22 a and 22 b should include the rotation stopper 97 to stop the unwanted rotation of the disc 100 sufficiently. However, to prevent the unintentional rotation of the disc 100 with more certainty, the three rotation stoppers 97 are preferably provided as shown in FIG. 102.

[0484] In this structure, while the disc 100 is held by the disc holders 21 a, 21 b, 22 a and 22 b, the rotation stoppers 97 that are in tight contact with the disc 100 do not allow the user to rotate the disc 100 so easily. Accordingly, in such a state, even if the user tries to rotate the disc 100 intentionally while pressing the disc 100 against the shutters 21 and 22, the disc 100 will not rotate so easily. Thus, even if relatively stiff dust has adhered to the nonwoven fabric that covers the shutters 21 and 22, the disc 100 will not get scratched by such dust because the user cannot rotate the disc 100 accidentally.

[0485] In addition, by providing the rotation stoppers 97, it is possible to prevent the disc 100 from moving inconstantly inside the disc storage portion.

[0486] As shown in FIG. 102, the shutters 21 and 22 include the concave portions 89 to which a nonwoven fabric is ultrasonic welded to partially cover the shutter surfaces that contact with the signal recording side 100A of the disc 100. In the preferred embodiment illustrated in FIG. 102, the concave portions 89 are formed so as to surround the outer periphery of those portions of the shutters 21 and 22 that contact with the signal recording side 100A. The concave portions 89 are also formed inside the outer periphery. However, the concave portions 89 may be formed in any regions other than those illustrated in FIG. 102 as long as the nonwoven fabric can be adhered to the shutters 21 and 22 just as intended. At these concave portions 89, the nonwoven fabric is ultrasonic welded to the shutters 21 and 22. When the nonwoven fabric is ultrasonic welded to the shutters 21 and 22, the nonwoven fabric might be partially cured or the resin material of the shutters 21 and 22 might partially protrude from the nonwoven fabric. Even so, those cured or protruding portions are received by the concave portions 89 and do not scratch the signal recording side 100A of the disc 100. When a nonwoven fabric is attached to the shutters 21 and 22, these concave portions 89 are preferably formed on the shutters 21 and 22 in any of the disc cartridges according to the first through eighteenth preferred embodiments of the present invention described above.

[0487] Embodiment 20

[0488] Hereinafter, a disc cartridge 320 according to a twentieth specific preferred embodiment of the present invention will be described with reference to the accompanying drawings.

[0489] First, the overall structure of the disc cartridge 320 will be outlined with reference to FIG. 104. The disc cartridge 320 includes lower shell 11, upper shell 12, first shutter 21, second shutter 22, disc stopper 23, shielding member 24 and rotational member 25. These members may be made of a synthetic resin, for example. However, there is no need to make all of these members of the same material. Instead, best materials may be selected for these members in view of the mechanical strengths or appearance required for them.

[0490] As shown in FIG. 104, the cartridge body 10 has an inner lower surface 11 u. The inner lower surface 11 u has a chucking opening 11 c and a head opening 11 h. The chucking opening 11 c allows a chucking member (e.g., a spindle motor for rotating the disc 100) to enter the disc cartridge 320 externally. The head opening 11 h allows a head, which reads and/or writes a signal (or information) from/on the signal recording side 100A of the disc 100, to enter the disc cartridge 320 and access a target location on the disc 100. The head opening 11 h is continuous with the chucking opening 11 c and reaches one side surface of the lower shell 11. Also, another opening 11 r is provided on another side surface of the lower shell 11, which is adjacent to the side surface having the head opening 11 h.

[0491] As will be described in detail later, the inner lower surface 11 u has two grooves 11 e and 11 f that receive the respective ends of convex portions 25 e and 25 f provided for the rotational member 25. These grooves 11 e and 11 f preferably do not reach the bottom of the inner lower surface 11 u. The inner lower surface 11 u further includes shaft holes 39 that receive shafts 37 and 38 provided for the first and second shutters 21 and 22, respectively. These shaft holes 39 preferably do not reach the bottom of the inner lower surface 11 u, either. In the preferred embodiment illustrated in FIG. 104, the shafts 37 and 38 are formed on the first and second shutters 21 and 22 and the shaft holes 39 are formed on the lower shell 11. Alternatively, shaft holes may be formed on the first and second shutters 21 and 22 and shafts may be formed on the lower shell 11.

[0492] The lower shell 11 further includes two positioning holes 11 w into which the cartridge positioning pins of the disc drive are inserted.

[0493] The upper shell 12 includes a circular disc window 12 w, which expands over the entire projection area of the disc 100. The disc window 12 w is defined by a cylindrical inner side surface 12 i of the cartridge body 10. The disc 100 can be inserted into the disc cartridge 320 through this disc window 12 w. The inner side surface 12 i has a notch 12 g.

[0494] The upper surface 12 d of the upper shell 12 also has a notch 12 j, which engages with the disc stopper 23. Although not shown, the disc stopper 23 and the upper surface 12 d of the upper shell 12 are provided with concavo/convex portions engaging with each other so that the disc stopper 23 does not disengage itself from the upper shell 12 so easily. When the disc stopper 23 is fitted with the upper shell 12, a portion of the disc stopper 23 protrudes into the disc window 12 w. In this preferred embodiment, to reduce the overall thickness of the cartridge body as much as possible, the notch 12 j is formed by removing a portion of the upper shell 12 completely. However, if the disc cartridge may have a thickness somewhat greater than that of the illustrated one, a concave portion may also be formed instead of the notch 12 j by removing a portion of the upper shell 12 incompletely, and a disc stopper engaging with such a concave portion may be prepared. For example, the notch and the disc stopper 23 of the disc cartridge 308 of the eighth preferred embodiment described above may be provided for the disc cartridge 320 of this twentieth preferred embodiment.

[0495] Another disc stopper 12 s is provided as an integral part of the upper shell 12 so as to expand into the window 12 w. The disc stoppers 12 s and 23 are used to prevent the disc 100 mounted from dropping down through the disc window 12 w during the time the first and second shutters 21 and 22 are opened and during the time the first and second shutters 21 and 22 are closed. These disc stoppers 12 s and 23 are particularly effective when this disc cartridge 320 is loaded into a vertically mounted disc drive. To remove the disc 100 from this disc cartridge 320, the disc stopper 23 needs to be disengaged and removed from the upper shell 12, and the disc 100 needs to be picked up from around the notch 12 j, for example. Optionally, three or more disc stoppers may be provided and/or each of the disc stoppers may be formed in any other shape or disposed at any position other than that illustrated in FIG. 104.

[0496] The upper and lower shells 12 and 11 are adhered, welded or joined (e.g., screwed up) together around their outer periphery, thereby forming a cartridge body 10. Also, the inner lower surface 11 u and the inner side surface 12 i of the cartridge body 10 together make up a disc storage portion for storing the disc 100 therein.

[0497] In the disc storage portion, the space defined by the inner side surface 12 i is wide enough to allow the disc 100 to rotate freely therein without contacting with the inner side surface 12 i. The top of the disc storage portion is opened as the disc window 12 w, and the first side 100B of the disc 100 stored in the disc storage portion is exposed entirely inside the disc window 12 w. On the other hand, the second side, i.e., the signal recording side 100A, of the disc 100 faces the inner lower surface 11 u.

[0498] By adopting such a structure, the cartridge 320 can be thinner than the conventional cartridge in which both sides of the disc are covered. In addition, the label side of the disc 100 can be displayed inside the disc window 12 w and the user can check the contents of the disc 100 that were printed on the label side (i.e., the first side) 100B. Moreover, by displaying the design of the label side, the disc cartridge including the disc can also have a good design.

[0499] The first and second shutters 21 and 22 are provided on the inner lower surface 11 u of the cartridge body 10. When the disc 100 is stored inside the disc cartridge 320, the first and second shutters 21 and 22 are located between the signal recording side (i.e., the second side) 100A of the disc 100 and the inner lower surface 11 u. The first and second shutters 21 and 22 have the shafts 37 and 38, respectively, which are inserted into the shaft holes 39 of the lower shell 11. Thus, the first and second shutters 21 and 22 rotate on the shafts 37 and 38, thereby covering or exposing the head and chucking openings 11 h and 11 c. When the first and second shutters 21 and 22 are opened, the second side 100A of the disc 100 is partially exposed inside the head opening 11 h.

[0500] The first and second shutters 21 and 22 are provided with notches so as to define a hole 20 h in a region that overlaps with the center hole 100 h of the disc 100 stored in the disc storage portion when the first and second shutters 21 and 22 are closed. The notches of the first and second shutters 21 and 22 are surrounded with convex portions 21 w and 22 w, respectively. When the first and second shutters 21 and 22 are closed, these convex portions 21 w and 22 w are in close contact with each other, thereby forming a ring 20 w that is adjacent to the inner circumference of the center hole 100 h of the disc 100. As already described in detail for the twelfth preferred embodiment, the ring 20 w prevents the dust from reaching the signal recording side 100A of the disc 100 by way of the center hole 100 h. Furthermore, the convex portions 21 w and 22 w have protrusions 35 and 36, respectively. That is to say, the top of the protrusions 35 and 36 is higher than that of the convex portions 21 w and 22 w.

[0501] Furthermore, to hold the disc 100 in the disc storage portion while the first and second shutters 21 and 22 are closed, the first shutter 21 includes a disc holder 21 b and the second shutter 22 includes disc holders 22 a and 22 b. These disc holders 21 b, 22 a and 22 b work just like the disc holders as described for the eighth through nineteenth preferred embodiments described above. In the eighth through nineteenth preferred embodiments, the first shutter 21 further includes the disc holder 21 a. In this twentieth preferred embodiment, however, the first shutter 21 includes a convex portion 27 a instead of the disc holder 21 a. The convex portion 27 a is provided to prevent the side surface of the disc 100 from being exposed through the head opening 11 h, which reaches one side surface of the lower shell 11, while the first and second shutters 21 and 22 are closed.

[0502] When closed, the first and second shutters 21 and 22 are not entirely in contact with each other along a line but have a plurality of contact portions that are not aligned with the line. More specifically, the shutters 21 and 22 have a first pair of contact portions 21 f and 22 f and a second pair of contact portions 21 g and 22 g. In this preferred embodiment, the contact portions 21 f and 22 f contact with each other approximately along the centerline of the disc cartridge 320. On the other hand, the contact portions 21 g and 22 g contact with each other along a line that defines a predetermined angle (e.g., approximately 15 degrees to approximately 18 degrees) with the centerline of the disc cartridge 320. The effects achieved by such a structure are already described in detail for the thirteenth preferred embodiment. As also described for the thirteenth preferred embodiment, the contact portions 21 g and 22 g partially overlap with each other in the thickness direction of the disc 100.

[0503] As will be described in detail later, the first and second shutters 21 and 22 include guide grooves 27 e and 28 f that respectively engage with the convex portions 25 e and 25 f of the rotational member 25. The guide grooves 27 e and 28 f extend vertically through the first and second shutters 21 and 22, respectively, so that the convex portions 25 e and 25 f of the rotational member 25 can reach the grooves 11 e and 11 f, respectively.

[0504] The rotational member 25 includes a sidewall 25 i and a disc supporting portion 25 a that is connected to the bottom of the sidewall 25 i. The sidewall 25 i has a cylindrical shape and has such a size as to surround the side surface of the disc 100 stored in the disc storage portion. The sidewall 25 i is discontinued by three notches 25 d, 25 g and 25 h. The disc supporting portion 25 a has a flat ring shape including a notch 25 c. As the first and second shutters 21 and 22 are opened, the rotational member 25 is rotated, thereby overlapping the notch 25 c with the head opening 11 h. A protrusion 25 m for moving the shielding member 24 is provided near the notch 25 d.

[0505] As described above, the convex portions 25 e and 25 f, which protrude toward the lower shell 11, are provided on the lower surface of the disc supporting portion 25 a. Furthermore, an opener/closer 25 j, which engages with the shutter opening/closing mechanism of a disc drive, is provided on the outer side surface of the sidewall 25 i. Alternatively, where the shutter opening/closing mechanism of the disc drive has a gear shape, a gear may be provided on the outer side surface of the sidewall 25 i instead of the opener/closer 25 j.

[0506] The shielding member 24 is disposed inside the notch 12 g of the inner side surface 12 i of the cartridge body 10. The structure and operation of the shielding member 24 will be described in detail later.

[0507] The respective members of the disc cartridge 320 are assembled in such a manner as satisfy the vertical positional relationship shown in FIG. 104. As a result, the lower and upper shells 11 and 12 are joined together so that the first and second shutters 21 and 22 are disposed on the lower shell 11 and that the rotational member 25 is located over the shutters 21 and 22.

[0508]FIG. 105 is a plan view illustrating the disc cartridge 320 with the upper shell 12 thereof removed. FIG. 106 is a cross-sectional view of the disc cartridge 320 as viewed along the line F-F shown in FIG. 105. The first and second shutters 21 and 22 are now closed.

[0509] As shown in FIG. 105, the disc holder 22 a of the second shutter 22 holds the disc 100 thereon inside the notch 25 d of the rotational member 25. The disc 100 is also held by the disc holders 21 b and 22 b of the first and second shutters 21 and 22 inside the notches 25 g and 25 h of the rotational member 25, respectively.

[0510] The opener/closer 25 j of the rotational member 25 is located inside the opening 11 r of the lower shell 11. The protrusions 35 and 36 of the first and second shutters 21 and 22 protrude into the center hole 10 h of the disc 100. The center of rotation of the rotational member 25 is substantially aligned with the center of the disc 100. That is to say, the rotational member 25 is disposed inside the disc storage portion so as to rotate substantially around the center of the disc 100.

[0511] The shafts 37 and 38 of the first and second shutters 21 and 22 are located under the disc supporting portion 25 a of the rotational member 25. As shown in FIG. 106, there is almost no gap between the top of the sidewall 25 i of the rotational member 25 and the bottom of the upper surface 12 d of the upper shell 12, thus regulating the vertical movement of the rotational member 25. Accordingly, the rotational member 25 can effectively prevent the shafts 37 and 38 of the first and second shutters 21 and 22 from being raised and disengaged from the shaft holes 39 of the lower shell 11 when the first and second shutters 21 and 22 rotate.

[0512] As shown in FIG. 106, the disc supporting portion 25 a of the rotational member 25 has a sloped upper surface 25 k, and therefore, the disc 100 is in contact with only a portion of the upper surface 25 k of the disc supporting portion 25 a near the sidewall 25 i. In such a structure, even if the ring-shaped disc supporting portion 25 a has its width increased to increase the mechanical strength of the rotational member 25, the upper surface 25 k is in contact with only a portion of the signal recording side 100A of the disc 100 around its outer periphery. Thus, the signal recording area is hardly in contact with the disc supporting portion 25 a. It should be noted that the top of that portion of the disc supporting portion 25 a that is in contact with the disc 100 is located at the same vertical level as the top of the convex portions 21 w and 22 w of the first and second shutters 21 and 22.

[0513] Next, it will be described how the first and second shutters 21 and 22 that is going to be closed or opened mount or dismount the disc 100 thereon/therefrom. FIG. 107 is a plan view illustrating the respective positions of the first and second shutters 21 and 22 and the rotational member 25 in a state where the first and second shutters 21 and 22 are closed. FIG. 108 is a cross-sectional view of the disc cartridge 320 as viewed along the line G-G shown in FIG. 107. FIG. 109 is a plan view illustrating the respective positions of the first and second shutters 21 and 22 and the rotational member 25 in a state where the first and second shutters 21 and 22 are opened. FIG. 110 is a cross-sectional view of the disc cartridge 320 as viewed along the line H-H shown in FIG. 109. In FIGS. 107 and 109, the disc 100 is indicated by the two-dot chain.

[0514] As shown in FIG. 107, while the first and second shutters 21 and 22 are closed, the disc holders 21 b, 22 a and 22 b protrude through the notches 25 g, 25 d and 25 h of the sidewall 25 i of the rotational member 25 toward the center of the disc 100, thereby holding the disc 100 thereon. As shown in FIG. 108, the disc holders 22 a and 22 b have downwardly tapered slopes 22 a′ and 22 b′ that are in contact with the outer edge of the first side 100B of the disc 100. Thus, the disc holders 22 a and 22 b press the disc 100 not only toward the center thereof but also toward the first and second shutters 21 and 22. Although not shown, the other disc holder 21 b is also in the same state. As a result, a portion of the signal recording side 100A of the disc 100 around the outer periphery thereof contacts with the disc supporting portion 25 a. Also, as already described for the twelfth preferred embodiment, the convex portions 21 w and 22 w of the first and second shutters 21 and 22 contact with a portion of the signal recording side 100A of the disc 100 near the center hole 100 h thereof (not shown). In this manner, the signal recording area on the signal recording side 100A of the disc 100 is shut off from the open air by the disc supporting portion 25 a of the rotational member 25 and by the convex portions 21 w and 22 w of the first and second shutters 21 and 22. Consequently, no dust or fine particles will be deposited on, or no scratches will be created on, the signal recording area.

[0515] The hole 20 h defined by the first and second shutters 21 and 22 has a diameter approximately equal to that of the center hole 100 h of the disc 100. Accordingly, even if this disc cartridge 320 is left upside down with the first and second shutters 21 and 22 thereof closed, no part of the signal recording side 100A of the disc 100 will be exposed inside the hole 20 h of the first and second shutters 21 and 22. For that reason, no dust or fine particles will be deposited on the signal recording side 100A of the disc 100.

[0516] To open the first and second shutters 21 and 22, the opener/closer 25 j is engaged with the shutter opening/closing mechanism of the disc drive, and is turned to the direction indicated by the arrow 25A. Then, the rotational member 25 starts to rotate inside the disc storage portion and the protrusions 25 e and 25 f also start to rotate around the center of the disc 100. The protrusions 25 e and 25 f are engaged with the guide grooves 27 e and 28 f, respectively. Accordingly, the protrusions 25 e and 25 f rotating go inside the guide grooves 27 e and 28 f in the directions indicated by the arrows 27E and 28F, respectively, while pressing the sidewalls of the guide grooves 27 e and 28 f. As the sidewalls of the guide grooves 27 e and 28 f are pressed by the protrusions 25 e and 25 f, the first and second shutters 21 and 22 rotate on the shafts 37 and 38 to the directions indicated by the arrows 21A and 22A, respectively.

[0517] The disc holder 21 b also starts to rotate on the shaft 37 to the direction indicated by the arrow 21A, while the disc holders 22 a and 22 b start to rotate on the shaft 38 to the direction indicated by the arrow 22A. Thus, the disc holders 21 b, 22 a and 22 b go away from the disc 100 and release the disc 100.

[0518] As the first and second shutters 21 and 22 are opened, the protrusions 35 and 36 on the first and second shutters 21 and 22 also rotate to the directions 21A and 22A, respectively. In the meantime, the disc 100 does not move. Accordingly, the protrusions 35 and 36 contact with the non-signal recording area 10 e on the signal recording side 100A of the disc 100. The protrusions 35 and 36 are located at a vertical level higher than that of the convex portions 21 w and 22 w. Thus, while the protrusions 35 and 36 are in contact with the signal recording side 100A, the convex portions 21 w and 22 w are out of contact with the signal recording side 100A. Consequently, it is possible to prevent the convex portions 21 w and 22 w from scratching the signal recording side 100A, or the signal recording area thereof, in particular.

[0519] As the rotational member 25 is rotated to a certain degree, the protrusions 25 e and 25 f will soon reach the ends of their guide grooves 27 e and 28 f, respectively, as shown in FIG. 109. Then, the first and second shutters 21 and 22 will be fully opened to expose the head and chucking openings 11 h and 11 c entirely.

[0520] At that time, the notch 25 c of the disc supporting portion 25 a of the rotational member 25 is aligned with the head opening 11 h, and no part of the disc supporting portion 25 a is exposed inside the head opening 11 h. Accordingly, when the first and second shutters 21 and 22 are fully opened, the head of the disc drive can access the disc 100 easily and is not interfered with by the rotational member 25.

[0521] Also, as shown in FIGS. 109 and 110, even when the first and second shutters 21 and 22 are opened, the protrusions 35 and 36 of the first and second shutters 21 and 22 are still in contact with the non-signal recording area 10 e on the signal recording side 100A of the disc 100. Thus, the signal recording area will not get scratched by the protrusions 35 and 36.

[0522] To close the shutters 21 and 22, the respective members should be moved in the opposite directions. That is to say, as the first and second shutters 21 and 22 are closed, the disc holders 21 b, 22 a and 22 b are getting closer to the disc 100 and eventually hold the disc 100 thereon. These operations have already been described in detail for the eighth through thirteenth preferred embodiments, and the description thereof will be omitted herein.

[0523] Next, the structure and operation of the shielding member 24 will be described. As shown in FIG. 111, the shielding member 24 includes a sidewall 24 d and a pair of shafts 24 b provided at the ends of the sidewall 24 d. At the bottom of the sidewall 24 d, a first contacting portion 24 a is provided. The first contacting portion 24 a needs to contact with the outer side surface of the disc 100 and has a curved surface having the same radius of curvature as the outer side surface of the disc 100. The backside of the sidewall 24 d is a second contacting portion 24 f. An arm 24 c is provided near each of the shafts 24 b and has a third contacting portion 24 e at the end thereof.

[0524] As shown in FIG. 112, the shielding member 24 is disposed at such a position that the shaft 24 b thereof is located between the upper surface 12 d of the upper shell 12 and the sidewall 25 i of the rotational member 25. As indicated by the arrow 24A, the shielding member 24 can swing on the shaft 24 b. A line that connects the respective centers of the shafts 24 b together is parallel to a tangent line defined with respect to the disc 100 and is located at a vertical level higher than the first side 100B of the disc 100.

[0525]FIGS. 113 and 114 illustrate cross sections of the shielding member 24 at one end and the center thereof while the first and second shutters 21 and 22 are closed. As shown in FIGS. 113 and 114, the sidewall 24 d is pressed toward the center of the disc 100 so that the convex portion 25 m of the rotational member 25 contacts with the second contacting portion 24 f of the shielding member 24 and that the first contacting portion 24 a contacts with the outer side surface of the disc 100. Thus, no dust or dirt will reach the signal recording side 100A of the disc 100 by way of the notch 25 c of the disc supporting portion 25 a (see FIG. 104). In this manner, the disc supporting portion 25 a and the shielding member 24 are in contact with the outer periphery of the disc 100 continuously, thereby preventing the dust or dirt from reaching the signal recording side 100A.

[0526] As the rotational member 25 is rotated to open the first and second shutters 21 and 22, the convex portion 25 m of the rotational member 25 goes away from the shielding member 24. As a result, no force is applied to the shielding member 24 toward the disc 100 anymore.

[0527] As the first and second shutters 21 and 22 are further opened and as the rotational member 25 is further rotated, the outer side surface of the sidewall 25 i of the rotational member 25 will soon contact with the third contacting portion 24 e of the shielding member 24, thereby pressing the sidewall 24 d outward. FIGS. 115 and 116 illustrate cross sections of the shielding member 24 at one end and the center thereof. As shown in FIG. 115, the outer side surface of the disc 100 has been out of contact with the first contacting portion 24 a of the shielding member 24. As a result, the disc 100 is now rotatable inside the disc storage portion.

[0528] In this manner, the shielding member 24 swings as the rotational member 25 is rotated, thereby alternately coming into contact with the outer side surface of the disc 100 and out of contact with the outer side surface of the disc 100 to allow the disc 100 to rotate freely.

[0529] As described above, in this preferred embodiment, the label side 100B of the disc 100 is displayed inside the disc cartridge 320. Thus, the disc cartridge 320 can have a good design and a reduced thickness.

[0530] In addition, the first and second shutters 21 and 22 can be opened and closed by rotating the rotational member 25. While the shutters 21 and 22 are closed, the disc 100 can be held firmly by the disc holders 21 b, 22 a and 22 b.

[0531] Furthermore, while the disc 100 is held inside the disc storage portion, the label side 100B of the disc 100 is exposed. Even so, the disc supporting portion 25 a of the rotational member 25, the protrusions 21 w and 22 w of the first and second shutters 21 and 22, and the shielding member 24 interlocked with the rotational member 25 together protect the signal recording side 100A of the disc 100 from dust, dirt or scratches.

[0532] In the twentieth preferred embodiment described above, the opening 11 r is provided on one side surface of the lower shell 11 so that the opener/closer 25 j for use to rotate the rotational member 25 is operated on the side surface that is adjacent to another side surface thereof including the head opening 11 h. Alternatively, the opener/closer 25 j may be provided on any other side surface of the cartridge body 10. As another alternative, a plurality of opener/closers may be provided as well. For example, the opener/closer 25 j of the preferred embodiment described above may be used as a first opener/closer and a protrusion may be provided as a second opener/closer for the sidewall 25 i of the rotational member 25 so as to be located inside the head opening 11 h. Optionally, as shown in FIG. 105, a protrusion 49 may be provided as a second opener/closer near the disc holder 22 a of the second shutter 22 so that the second shutter 22 can be operated directly. In that case, as the second shutter 22 is moved, the rotational member 25 rotates, thereby moving the first shutter 21 synchronously.

[0533] In the twentieth preferred embodiment described above, the shielding member 24 prevents dust from reaching the signal recording side 100A of the disc 100 by way of the notch 25 c of the disc supporting portion 25 a. Alternatively, any other structure may be used to prevent dust from entering the disc cartridge 320 through the notch 25 c.

[0534] For example, as schematically illustrated in FIG. 117, the notch 12 g of the inner side surface 12 i of the cartridge body 10 may be closed up by extending the inner side surface 12 i, and the disc holder 22 b of the second shutter 22 (not shown) may be disposed at a position that is symmetrical to the notch 12 g with respect to the center of the disc 100. Just like the disc holder of the thirteenth preferred embodiment described above, the disc holder 22 b needs to be movable toward the center of the disc 100 and an elastic force needs to be applied to the disc holder 22 b toward the center of the disc 100, too. As another alternative, as in the disc holder of the nineteenth preferred embodiment described above, an elastic member may be provided for a portion of the disc holder 22 b that contacts with the disc 100 so that the elastic force applied therefrom presses the disc 100 toward the center thereof as shown in FIG. 118.

[0535] Specifically, such a disc holder 22 b contacts with the disc 100 and holds it thereon, thereby pressing the outer side surface of the disc 100 toward the notch 25 c of the inner side surface 121 of the cartridge body 10. The sizes of the disc storage portion and the disc 100 are almost equal to each other. Accordingly, the radius of curvature of the inner side surface 12 i is approximately equal to that of the outer side surface of the disc 100. As a result, the outer side surface of the disc 100 closely contact with the inner side surface 12 i of the cartridge body 10. Thus, the inner side surface 12 i and the disc supporting portion 25 a together prevent dust from reaching the signal recording side 100A of the disc 100.

[0536] Such a structure needs no shielding member 24, thus simplifying the structure of the disc cartridge.

[0537] Embodiment 21

[0538] Hereinafter, a disc cartridge 321 according to a twenty-first specific preferred embodiment of the present invention will be described.

[0539]FIG. 119 is an exploded perspective view of the disc cartridge 321 of the twenty-first preferred embodiment. The disc cartridge 321 of this twenty-first preferred embodiment is different from the disc cartridge 320 of the twentieth preferred embodiment shown in FIG. 104 in that the disc cartridge 321 includes a disc stopper 55 of a different shape and a removal history hole 11 n on the lower shell 11 thereof. Thus, the following description of the twenty-first preferred embodiment will be focused on the disc stopper 55 and the removal history hole 11 n.

[0540] As shown in FIG. 119, the disc stopper 55 is provided near a side surface of the cartridge body, consisting of the upper and lower shells 12 and 11, so as to face another side surface of the cartridge body having the head opening 11 h. A shaft 55 a is provided near one end of the longer side of the disc stopper 55, while the other end thereof includes a latching portion 55 d with a protrusion 55 e.

[0541] The upper shell 12 includes a shaft hole 12 m to receive the shaft 55 a of the disc stopper 55, an opening 12 p into which the latching portion 55 d is inserted, and another hole 12 n to receive the protrusion 55 e of the latching portion 55 d. The upper shell 12 also includes a recessed portion 12 k so that the upper surface of the disc stopper 55 is leveled with the upper surface 12 d of the upper shell 12 when the disc stopper 55 is attached to the upper shell 12. The shaft hole 12 m and the opening 12 p are formed in the recessed portion 12 k. While the disc stopper 55 is protruding into the disc window 12 w and over the disc 100 stored, the protrusion 55 e of the latching portion 55 d is inserted into the hole 12 n, thereby fixing the disc stopper 55 onto the upper shell 12.

[0542] The lower shell 11 includes the removal history hole 11 n. FIG. 120 illustrates the removal history hole 11 n and its surrounding members to a larger scale. As shown in FIG. 120, the removal history hole 11 n is almost covered with a cap member 56. Specifically, the cap member 56 is connected to the inner sidewall of the removal history hole 11 n by way of connectors 56 a. The cap member 56 has a columnar (or pin) shape and includes a protrusion 56 b at the top thereof.

[0543] The center of the removal history hole 11 n is aligned with that of the shaft hole 12 m of the upper shell 12 and that of the shaft 55 a of the disc stopper 55. As will be described in detail later, the cap member 56 is engaged with the disc stopper 55. Accordingly, when the disc stopper 55 is rotated on its shaft 55 a, a rotational force is applied to the cap member 56 in such a direction as to rotate the cap member 56 around its axis 56 c. As a result, the connectors 56 a are snapped off, the cap member 56 drops off from the lower shell 11, and the removal history hole 11 n is fully opened.

[0544] When the disc cartridge 321 is manufactured, the disc 100 is stored in the disc storage portion that is defined by the inner side surface 12 i of the upper shell 12. Thereafter, when the user rotates the disc stopper 55 to remove the disc 100 from the disc cartridge 321, the cap member 56 will drop off and the removal history hole 11 n will be opened. Once the cap member 56 has been eliminated, the removal history hole 11 n remains open even if another disc 100 is stored in the disc cartridge 321 by operating the disc stopper 55. In other words, as long as the removal history hole 11 n is closed with the cap member 56, the disc 100 stored in the disc cartridge 321 should be the disc that was originally stored there during the manufacturing process of the disc cartridge 321. On the other hand, if the removal history hole 11 n is open, then the disc 100 stored in the disc cartridge 321 might be different from the original disc that was stored there during the manufacturing process of the disc cartridge 321.

[0545] A disc drive to be loaded with this disc cartridge 321 senses the opened or closed state of this removal history hole 11 n, thereby controlling the read or write operation in accordance with the result. For example, suppose the disc cartridge 321 manufactured should store a disc to be read from or written to in compliance with only a predetermined standard. In that case, if the disc drive finds the removal history hole 11 n of the disc cartridge 321 closed, the disc drive recognizes the disc stored in the disc cartridge 321 as readable or writable in compliance with the predetermined standard. Then, the disc drive can quickly perform a read or write operation on the disc in compliance with that standard. On the other hand, if the disc drive finds the removal history hole 11 n of the disc cartridge 321 opened, the disc drive senses the disc stored in the disc cartridge 321 as an unknown type. In that case, to recognize the type of the disc that is stored in the disc cartridge 321, the disc drive applies various test signals to the disc first. Next, in accordance with the test results, the disc drive reads or writes a signal from/on the disc under optimized conditions.

[0546] Hereinafter, the structure of the disc stopper 55 and the operation of exchanging the original disc 100 for a different one will be described in further detail.

[0547]FIG. 121 illustrates a state in which the disc stopper 55 protrudes over the disc 100 to prevent the disc 100 from dropping through the disc window 12 w of the upper shell 12. It is in such a state that the disc cartridge 321 is either stored or inserted into a disc drive. FIGS. 122 and 123 are cross-sectional views illustrating portions of the disc cartridge 321 around the shaft 55 a and the latching portion 55 d, respectively, as viewed along the line J-J shown in FIG. 121. FIG. 124 is a cross-sectional view illustrating portions of the disc cartridge 321 as viewed along the line K-K shown in FIG. 121.

[0548] As shown in FIG. 121, the disc stopper 55 is opposed to another disc stopper 12 s that protrudes from the upper shell 12 toward the center of the disc window 12 w. The disc stopper 55 has an arched concave side surface 55 f along the length thereof.

[0549] As shown in FIG. 122, the upper shell 12 includes a cylindrical boss 12 q, inside which the shaft hole 12 m is defined. The shaft 55 a of the disc stopper 55 is inserted into the shaft hole 12 m as described above. The shaft 55 a includes a protrusion 55 p at the bottom thereof so as not to be disengaged from the shaft hole 12 m easily. Also, inside the shaft 55 a, an inner space having an inside diameter that is approximately equal to the diameter of the removal history hole 11 n is defined. The cap member 56 is stored inside that inner space. The protrusion 56 b of the cap member 56 is fitted with a concave portion 55 b of the disc stopper 55. The center of the shaft 55 a of the disc stopper 55 is aligned with the axis of rotation 56 c of the cap member 56. Also, as described above, the cap member 56 is connected to the inner sidewall of the removal history hole 11 n by way of the connectors 56 a. The connectors 56 a are thinner than the bottom of the lower shell 11.

[0550] As shown in FIG. 123, the latching portion 55 d at the other end of the disc stopper 55 is inserted into the opening 12 p of the upper shell 12 and in contact with the back surface of the upper shell 12. The protrusion 55 e, provided at the end of the latching portion 55 d, is fitted with the hole 12 n of the upper shell 12. The disc stopper 55 further includes a bridge portion 55 f with a reduced thickness so that the latching portion 55 d is partially deformed elastically when the protrusion 55 e is depressed in the direction indicated by the arrow 55A in FIG. 123. Furthermore, the latching portion 55 d of the disc stopper 55 and its associated contact surface of the upper shell 12 are provided with stepped portions 55 g and 12 o, respectively, which engage with each other. These stepped portions 55 g and 120 are provided to prevent the latching portion 55 d and its surrounding portions from being raised over the upper shell 12 when the disc stopper 55 is rotated.

[0551] To remove the disc 100 from the disc cartridge 321, the protrusion 55 e that is engaged with the hole 12 n of the upper shell 12 is depressed in the direction 55A as shown in FIGS. 123 and 124, and at the same time, the disc stopper 55 is rotated to the direction indicated by the arrow 55B shown in FIG. 121. Then, as shown in FIG. 124, the bridge portion 55 f of the latching portion 55 d is deformed elastically and the latching portion 55 d slides while the top of the protrusion 55 e keeps contact with a slope 12 v on the back surface of the upper shell 12. Since the slope 12 v is provided on the back surface of the upper shell 12, the latching portion 55 d can easily reach the dashed-line location shown in FIG. 124 even if no great force is applied thereto along the slope 12 v. To make the elastically deformed bridge portion 55 f of the latching portion 55 d recover its original shape, when the latching portion 55 d reaches this position, the top of the protrusion 55 e is located at the same vertical level as it was when engaged with the hole 12 n.

[0552] In the meantime, the disc stopper 55 rotates to the direction 55B around the center 55 c of the shaft 55 a thereof as shown in FIG. 122. As a result, a force that rotates the cap member 56 to the direction 55B around its axis of rotation 56 c is applied to the cap member 56, thereby snapping the connectors 56 a off and dropping the cap member 56 off.

[0553]FIG. 125 illustrates a state where the disc stopper 55 has moved to such a position as allowing the user to remove the disc 100 from the disc cartridge 321. At this point in time, the latching portion 55 d has already contacted with the inner side surface of the upper shell 12 as shown in FIG. 124, and therefore, the disc stopper 55 can no longer be rotated to the direction 55B.

[0554] As shown in FIG. 125, just a portion of the disc stopper 55 still protrudes into the disc window 12 w. However, if the disc 100 is slightly moved toward the disc stopper 12 s, the disc stopper 55 will not be located over the disc 100 anymore. Then, the user can remove the disc 100 from the disc cartridge 321 by gripping the disc 100 with a finger laid on the center hole 100 h thereof and lifting the edge of the disc 100 from around the disc stopper 55 on the upper shell 12.

[0555]FIGS. 126 and 127 are cross-sectional views illustrating portions of the disc cartridge 321 around the shaft 55 a and the latching portion 55 d, respectively, as viewed along the line J-J shown in FIG. 125. As described above, while the disc stopper 55 is being rotated, the cap member 56 drops off. Accordingly, when the disc stopper 55 has moved to the limit, the removal history hole 11 n will be fully opened as shown in FIG. 126. Also, the protrusion 55 e of the latching portion 55 d engages with a recessed portion 12 r of the upper shell 12 as shown in FIG. 127. Thus, the elastically deformed bridge portion 55 f of the latching portion 55 d recovers its original shape.

[0556] After the originally stored disc 100 is removed from the disc cartridge 321, another disc 100 is stored in the disc cartridge 321 and then the disc stopper 55 is rotated in the direction opposite to the arrowed direction 55B. When the disc stopper 55 gets to its original position shown in FIG. 121, the protrusion 55 e of the latching portion 55 d is engaged with the hole 12 n of the upper shell 12 again and the disc stopper 55 is fixed onto the upper shell 12 again.

[0557] To replace the disc 100 with still another disc, the disc stopper 55 may be operated just as described above. However, since the cap member 56 has already been removed, no cap member 56 will be dropped off by the disc stopper 55 rotating.

[0558] In the disc cartridge 321 of this twenty-first preferred embodiment, the disc stopper 55 has the arched concave side surface 55 f. Thus, even if the disc stopper 55 is not rotated so much, the disc stopper 55 can soon stop protruding over the disc 100. Also, since the disc stopper 55 is rotated to just a small degree, the latching portion 55 d of the disc stopper 55 can keep contacted and engaged with the upper shell 12. Accordingly, even when the disc 100 is removed from the disc cartridge 321, both ends of the disc stopper 55 still can keep contact with the upper shell 12 and the disc stopper 55 can maintain sufficient mechanical strength. Thus, even if the user dropped the disc cartridge 321 by mistake or pressed the disc stopper 55 too strongly in removing the disc 100 therefrom, the disc stopper 55 would not be broken.

[0559] In addition, according to this preferred embodiment, when the disc stopper 55 is rotated, the removal history hole 11 n is opened. Accordingly, unlike the conventional disc cartridge, the user does not have to snap off the tab of the history hole.

[0560] Furthermore, in the preferred embodiment described above, the cap member 56 has a columnar shape. Alternatively, the cap member 56 may also have any other shape as long as the cap member 56 can be connected to the lower shell 11 in such a manner as to cover the removal history hole 11 n at least partially and can be removed as the disc stopper 55 rotates. For example, the cap member may include: a tab provided for the removal history hole 11 n; and an auxiliary member, which is provided between the disc stopper 55 and the tab and snaps the tab off as the disc stopper 55 rotates.

[0561] Also, in the preferred embodiment described above, the disc stopper 55 is moved from a first position, at which the disc 100 is held tight so as not to drop from the disc cartridge 321, to a second position, at which the disc 100 is ready to remove from the disc cartridge 321, or vice versa, by rotating the disc stopper 55 parallelly to the disc 100. Alternatively, the disc stopper 55 may be moved in a different direction.

[0562]FIGS. 128 and 129 illustrate an alternative disc stopper 57 that slides parallelly to the side surfaces of the disc cartridge 321. The disc stopper 57 also has an arched concave side surface 57 f along the length thereof. Specifically, FIG. 128 illustrates a state where the disc 100 is held by the disc stopper 57. As shown in FIG. 128, in such a state, the disc stopper 57 is partially protruded over the disc 100. To remove the disc 100, the disc stopper 57 is moved in the direction indicated by the arrow 57A (i.e., vertically to the longer side of the disc stopper 57) as shown in FIG. 129. The side surfaces 57 a of the disc stopper 57 are preferably provided with convex or concave portions that engage with the upper shell 12 so that the disc stopper 57 is not disengaged from the upper shell 12 so easily.

[0563] The side surface 57 f of the disc stopper 57 is also arched and recessed. Thus, just by moving the disc stopper 57 only slightly, the disc stopper 57 can soon stop protruding over the disc 100. For that reason, the disc 100 can be removed from the disc cartridge 321 while most of the disc stopper 57 keeps contact with the upper shell 12. As a result, even when the discs 100 are exchanged, the disc stopper 57 does not lose its mechanical strength at all.

[0564]FIGS. 130 and 131 illustrate another alternative disc stopper 58, which rotates on a shaft 58 a that is secured to the upper shell 12 at both ends of its longer side. In this alternative preferred embodiment, an elastic force is preferably applied from a spring, for example, to the disc stopper 58 so that the disc stopper 58 keeps contact with the upper shell 12 as shown in FIG. 130. If necessary, the disc stopper 58 may be rotated to the position shown in FIG. 131. However, since the disc stopper 58 also has an arched concave side surface 58 f along the length thereof, the disc 100 may be removed just by rotating the disc stopper 58 slightly from the position shown in FIG. 130.

[0565] If the disc stopper 57 or 58 is provided for the disc cartridge 321, the disc cartridge 321 may have a mechanism that removes the cap member as the disc stopper 57 or 58 slides or rotates. Alternatively, the cap member that covers the removal history hole may not be interlocked with the disc stopper 57 or 58. In that case, the disc cartridge may have a mechanism that allows the disc stopper 57 or 58 to slide or rotate only after the user has removed the cap member.

[0566] Embodiment 22

[0567] Hereinafter, a disc cartridge 322 according to a twenty-second specific preferred embodiment of the present invention will be described.

[0568]FIG. 132 is a plan view illustrating the disc cartridge 322 of the twenty-second preferred embodiment. FIG. 133 is a cross-sectional view of the disc cartridge 322 as viewed along the line L-L shown in FIG. 132. Just like the disc cartridge of the twentieth preferred embodiment as already described with reference to FIGS. 117 and 118, the disc cartridge 322 can also prevent dust from entering the disc cartridge 322 through the notch 25 c of the disc supporting portion 25 a without using any shielding member. Although not shown in detail in FIG. 132, the disc cartridge 322 also includes the first and second shutters 21 and 22, rotational member 25 and disc stopper 55 as already described for the twentieth and twenty-first preferred embodiments. Each of these members may have the same structure as the counterpart of the twentieth or twenty-first preferred embodiment described above.

[0569] In the disc cartridges 320 and 321 of the twentieth and twenty-first preferred embodiments shown in FIGS. 104 and 119, respectively, the sidewall 12 i of the upper shell 12 includes the notch 12 g, which is located at the same position as the notch 25 c of the disc supporting portion 25 a while the first and second shutters 21 and 22 are closed.

[0570] Meanwhile, in the disc cartridge 322 of this twenty-second preferred embodiment, the sidewall 12 i does not have the notch 12 g but is continuous around the circumference of the disc 100. Also, as shown in FIG. 134, an extended sidewall 12 i′ is provided under the sidewall 12 i so as to contact with the outer side surface of the disc 100. The extended sidewall 12 i′ is located at a position corresponding to the notch 12 g.

[0571] The sidewall 12 i defines the disc window 12 w, and therefore has a greater radius of curvature than the disc 100. On the other hand, the extended sidewall 12 i′ has the same radius of curvature as the disc 100 as shown in FIG. 135. As shown in FIG. 132, the center of the cylinder that is defined by the sidewall 12 i is aligned with the center C1 of the disc storage portion. Meanwhile, the center of the curvature that is defined by the extended sidewall 12 i′ is aligned with a point C2. That is to say, the point C2 is offset from the point C1. It should be noted that the sidewall 25 i of the rotational member 25 defines a cylinder, of which the center is aligned with the center C1 of the disc storage portion, and rotates around the point C1.

[0572] Also, the disc holder 22 b holds the disc 100 thereon such that the center of the disc 100 is aligned with the point C2. Although only one disc holder 22 b is illustrated in FIG. 132, the two other disc holders 21 b and 22 a (not shown) also hold the disc 100 thereon so that the center of the disc 100 is aligned with the point C2. In such a position, the disc supporting portion 25 a supports the disc 100 thereon without contacting with the signal recording side (i.e., the back surface) of the disc 100. Accordingly, the center of the disc supporting portion 25 a is also offset from the point C1. The distance between the points C1 and C2 is changeable with the radius of the cylinder defined by the sidewall 12 i and the radius of the disc 100. For example, if the disc 100 has a diameter of 5 inches, the distance between the points C1 and C2 is preferably from about 0.5 mm to about 1.5 mm. The reason is as follows. Specifically, if the distance is smaller than about 0.5 mm, then the disc 100 rotating might contact with the sidewall 12 i because the disc 100 will flutter when the disc 100 is rotated inside the disc cartridge 322 that has been loaded into the disc drive. However, if the distance between the points C1 and C2 is greater than about 1.5 mm, then the gap between the disc 100 and the sidewall 12 i of the disc storage portion will be so wide that a lot of dust or other dirt might enter the disc cartridge 322 through the gap.

[0573]FIG. 137 is a cross-sectional view illustrating the disc holder 22 b and its surrounding portions of the disc cartridge 322 as viewed along the line L-L shown in FIG. 132. As already described for the twentieth preferred embodiment, the upper surface 25 k of the disc supporting portion 25 a is sloped, and the disc 100 contacts with only a portion of the upper surface 25 k of the disc supporting portion 25 a near the sidewall 25 i (not shown in FIG. 137) of the rotational member 25. In this preferred embodiment, that portion of the upper surface 25 k of the disc supporting portion 25 a around the sidewall 25 i is parallel to the bottom of the lower shell 11. Accordingly, while the first and second shutters 21 and 22 are closed so that the disc 100 gets held by the disc holders 21 b, 22 a (not shown) and 22 b, the disc 100 contacts with the disc supporting portion 25 a in this region 25 b. The inner circumference of the region 25 b in which the disc supporting portion 25 a contacts with the disc 100 is defined by the dashed circle 25 n as shown in FIG. 132.

[0574] As shown in FIG. 132, the region 25 b of the disc supporting portion 25 a is located almost around the outer periphery of the disc 100 but discontinued by the notch 25 c. Also, the inner circumference 25 n of the region 25 b defines a circle of which the center is aligned with the point C2. On the other hand, the outer circumference of the region 25 b is defined by the outer circumference of the disc 100. Accordingly, the region 25 b is a notched ringlike region that is defined by two concentric circles having their centers aligned with the point C2 and that is discontinued by the notch 25 c.

[0575] While the first and second shutters 21 and 22 (not shown in FIG. 132) are closed so that the disc 100 gets held by the disc holders 21 b, 22 a (not shown) and 22 b of the first and second shutters 21 and 22, the center of the disc 100 is aligned with the point C2. Also, since the radius of curvature of the disc 100 is equal to that of the extended sidewall 12 i′, the outer side surface of the disc 100 comes into tight contact with the extended sidewall 12 i′ at the position where the notch 12 g exists in other disc cartridges. In other words, the center of the disc 100 held by the disc holders 21 b, 22 a and 22 b is offset from the center of the disc storage portion so that the outer side surface of the disc 100 comes into contact with, and gets held by, the extended sidewall 12 i′.

[0576] Also, while the first and second shutters 21 and 22 (not shown in FIG. 132) are closed, the center of the notched ringlike region 25 b, in which the disc supporting portion 25 a and the disc 100 contact with each other, is also offset from the center of the disc storage portion. Accordingly, the signal recording side (i.e., the back surface) of the disc 100 contacts with the disc supporting portion 25 a around the outer periphery thereof and the outer side surface of the disc 100 closely contacts with the extended sidewall 12 i′ where the disc supporting portion 25 a is discontinued by the notch 25 c.

[0577] On the other hand, around the center hole 100 h, the disc 100 is in contact with the convex portions 21 w and 22 w of the first and second shutters 21 and 22 as already described for the twentieth preferred embodiment. Thus, the signal recording area of the disc 100 is completely shut off from the air, and no dust will be deposited on the signal recording area of the disc 100.

[0578] Also, as shown in FIGS. 136 and 137, the disc holder 22 b of the second shutter 22 of the disc cartridge 322 has a tapered bottom 26 c, while a recessed portion 11 x is provided for the lower shell 11 to receive the bottom 26 c of the disc holder 22 b. Accordingly, if the thickness or the diameter of the disc 100 is not quite equal to, but slightly greater than, the standard one, then a portion 26 b of the second shutter 22 is deformed elastically near the end of the recessed portion 11 x of the lower shell 11 as shown in FIG. 137. As a result, the sloped portion 22 b′ of the disc holder 22 b contacts with the outer edge of the disc 100 and the first and second shutters 21 and 22 can firmly hold the disc 100 thereon without allowing the disc 100 to move inconstantly. Also, as the second shutter 22 is deformed elastically, the disc holder 22 b applies an elastic force to the disc 100 toward the center thereof. Consequently, the disc 100 is pressed against, and comes into closer contact with, the extended sidewall 12 i′ as shown in FIGS. 132 and 134. Then, the unwanted deposition of dust on the signal recording area of the disc 100 can be prevented with even more certainty.

[0579] To get the disc 100 held just as intended irrespective of the variation in thickness or diameter of the disc 100, the disc cartridge 322 may be designed such that the second shutter 22 is slightly deformed elastically as shown in FIG. 137 when the thickness or the diameter of the disc 100 to be held is approximately equal to the center value of its standard range and that the second shutter 22 is hardly deformed elastically as shown in FIG. 136 when the thickness or the diameter of the disc 100 to be held is approximately equal to the lower limit of that range.

[0580] As described above, according to this preferred embodiment, no dust will be deposited on the signal recording area of the disc 100 even if no shielding member 24 is provided. That is to say, neither the shielding member 24 nor the mechanism for interlocking the shielding member 24 with the rotational member 25 is needed, thus simplifying the structure of the disc cartridge significantly.

[0581] Embodiment 23

[0582] Hereinafter, a disc cartridge 323 according to a twenty-third specific preferred embodiment of the present invention will be described.

[0583] The disc cartridge according to any of various preferred embodiments of the present invention described above stores a disc therein with one side of the disc exposed unlike the conventional disc cartridge. Thus, the disc cartridge of the present invention can be thinner than the conventional one. Also, since the label side of the disc is displayed, the overall disc cartridge can have a good design.

[0584] However, since one side of the disc is supposed to be exposed inside this disc cartridge, the user may touch the label side of the disc. Accordingly, a careless user might press the label side of the disc too strongly. Thus, the disc cartridge of this type should hold the disc in such a manner as to prevent the signal recording side of the disc from getting scratched or the disc itself from being deformed even in such a situation. In view of these potential unfavorable situations, the present inventors carried out an intensive research on how the disc should be held to have its signal recording side protected from scratches, for example.

[0585]FIG. 138 illustrates a holding structure 59 (e.g., the disc supporting portion 25 a) for holding the disc 100 thereon and a space to be provided under the signal recording area food of the disc 100 so that the signal recording area 100 d will not get scratched by the holding structure 59 even if the disc 100 is pressed by the user too strongly. It should be noted that the sizes of some portions of the holding structure 59 are not to scale in FIG. 138 so as to make the features of the holding structure 59, which defines that space, clearly understandable. Accordingly, the aspect ratio illustrated in FIG. 138 is different from the actual one.

[0586] If plenty of space was allowed under the disc 100, the height of the space had only to be slightly greater than the maximum flexure of the disc 100. This is because, in that case, the disc 100 would never contact with the holding structure 59 no matter how much the disc 100 was deformed. However, a disc cartridge with such an ample space would be too thick. So the space under the disc 100 should actually be minimized. To minimize the space, the disc 100 needs to be held so as to have as small flexure as possible. And to reduce the flexure, portions of the disc 100 to be held by the holding structure 59 are preferably as close to the signal recording area 100 d of the disc 100 as possible. As shown in FIG. 138, the portions of the holding structure 59, on which the signal recording side 100A of the disc 100 is supported, are defined by an inner radius Rin and an outer radius Rout. That is to say, the disc 100 is held not only by the inside portion of the holding structure 59 that is located inside the inner radius Rin but also by the outside portion of the holding structure 59 that is located outside of the outer radius Rout. The “inner radius Rin” is herein supposed to be a distance from the center of the disc 100 to a point that is located closer to the center of the disc 100 than, and defined near, the inner periphery of the signal recording area 100 d. On the other hand, the “outer radius Rout” is herein supposed to be a distance from the center of the disc 100 to a point that is located closer to the outer edge of the disc 100 than, and defined near, the outer periphery of the signal recording area 100 d. As described above, these two points that define the inner and outer radii Rin and Rout are as close to the signal recording area 100 d as possible. For example, if the disc 100 has a diameter of about 5 inches (i.e., a radius of about 60 mm), then the inner radius Rin is preferably about 20 mm and the outer radius Rout is preferably about 59 mm.

[0587] The space 69 b to be provided under the disc 100 to prevent the signal recording area 100 d from getting scratched is defined in the following manner. First, the height (or the depth) S (mm) of the space 69 b is defined. Next, three circles 69 d, 69 e and 69 f are defined. Specifically, the circle 69 d has a radius that is equal to the outer radius Rout and is defined on the signal recording side 100A; the circle 69 e has a radius obtained by (Rout—1.2S) and is defined on a plane that is parallel to, and 0.3S mm separated from, the signal recording side 100A; and the circle 69 f has a radius obtained by (Rout—16.2 S) and is defined on a plane that is parallel to, and S mm separated from, the signal recording side 100A. A truncated cone, of which the top and bottom are defined by the circles 69 d and 69 e, respectively, has a side surface 59 a, while another truncated cone, of which the top and bottom are defined by the circles 69 e and 69 f, respectively, has a side surface 59 b.

[0588] A circular cylinder is also defined so as to have a circular bottom with the radius Rin as measured from the center of the disc 100 and a side surface 59 d with the height (or depth) S as measured from the signal recording side 100A. The space 69 b to be provided under the signal recording area 100 d is obtained by removing the circular cylinder, defined by the side surface 59 d, from the two-stepped truncated cone defined by the side surfaces 59 a and 59 b.

[0589] The S value defines the height of the space 69 b. Accordingly, the greater the S value, the less likely the signal recording area 100 d gets scratched even if the disc 100 is deformed. However, as the S value is increased, the disc cartridge increases its thickness. Thus, to make a thin disc cartridge, the S value is preferably as small as possible. The present inventors discovered and confirmed via experiments that even an S value of about 1 mm was great enough to protect the signal recording area 100 d of the disc 100 from scratches as long as the flexure of the disc 100 was caused by a pressure that was manually applied by the user.

[0590] On the other hand, a clamp area 100 e′ of the disc 100 preferably does not contact with the holding structure 59 within the region defined by the inner radius Rin. The reason is as follows. When the disc cartridge 323 is loaded into a disc drive to read and/or write a signal from/on the disc 100, the clamp area 100 e′ will contact with a turntable or a clamper. Accordingly, if this area 100 e′ has been scratched or partially covered with dust, then the disc 100 cannot get chucked as intended. The clamp area 100 e′ is defined by two concentric circles that have diameters of about 22 mm and about 33 mm, respectively, and have their centers aligned with that of the disc 100. The clamp area 100 e′ accounts for just a small percentage of the overall area of the disc 100. Thus, even if the user presses the disc 100 from over the clamp area 100 e′, the disc 100 will be hardly bent. For that reason, only if a space 69 a is provided so as to contact with the entire clamp area 100 e′, the space 69 a may have any height (or depth).

[0591]FIG. 139 schematically illustrates how much the disc 100 is deformed if the space 69 b is provided under the disc 100 with the S value set to 1 mm and a pressure is applied onto the disc 100 toward the space 69 b. The present inventors discovered and confirmed via experiments that the pressure that was applied manually onto the disc 100 by the user never exceeded 3 kg. The present inventors also discovered that even when the maximum pressure of 3 kg was applied, the disc 100 was bent fully within the space 69 b and never contacted with the side surface 59 a or 59 b.

[0592] In this case, the space 69 b defined has minimum required dimensions to prevent the signal recording area 100 d of the disc 100 from getting scratched. Accordingly, a greater space may be provided under the signal recording area 100 d of the disc 100. That is to say, the space 69 b may be provided beyond the side surfaces 59 a and 59 b as shown in FIGS. 140 and 141. In that case, however, to sufficiently increase the mechanical strength of the outside portion of the holding structure 59 to hold the outer periphery of the disc 100 thereon, a reinforced portion 59′ or 59′ is preferably provided adjacent to the outside portion. The side surfaces 59 a and 59 b can be used effectively to determine the allowable shapes of those reinforced portions 59′ and 59 w.

[0593] Hereinafter, a disc cartridge that was designed in view of these considerations will be described specifically. FIG. 142 is a plan view of the disc cartridge 323. FIG. 143 is a cross-sectional view thereof as viewed along the line P-P shown in FIG. 142. FIG. 144 is an exploded perspective view of the disc cartridge 323. In the disc cartridge 323 of this twenty-third preferred embodiment, each member that is equivalent to the counterpart of the disc cartridge according to the twentieth, twenty-first or twenty-second preferred embodiment described above is identified by the same reference numeral.

[0594] Just like the disc cartridge 322 of the twenty-second preferred embodiment described above, the disc cartridge 323 has no shielding member but holds the disc 100 thereon by bringing the outer side surface of the disc 100 into contact with the sidewall 12 i of the upper shell 12.

[0595] More specifically, while the first and second shutters 21 and 22 are closed, the disc cartridge 323 gets the disc 100 held by the disc holder 21 b of the first shutter 21 and the disc holders 22 a and 22 b of the second shutter 22 as shown in FIGS. 142 and 144. In this case, the outer side surface of the disc 100 contacts with the sidewall 12 i of the upper shell 12 where the notch 25 c of the rotational member 25 is located. Also, the center of the disc 100 is aligned with the point C2. The inner circumference of the region, in which the disc supporting portion 25 a of the rotational member 25 contacts with the disc 100, has its center aligned with the point C2 so that the region contacts with the signal recording side 100A of the disc 100 equally. On the other hand, the center of the sidewall 25 i of the rotational member 25 is aligned with the point C1.

[0596] As shown in FIGS. 142 and 144, a ring 20 w, consisting of convex portions 21 w and 22 w, is provided around the hole 20 h that is defined by the first and second shutters 21 and 22 of the disc cartridge 323. The hole 20 h corresponds to the center hole 100 h of the disc 100. Another pair of convex portions 35 d and 36 d is provided so as to be separated from the ring 20 w by a predetermined distance. The upper surface of the convex portions 35 d and 36 d is leveled with that of the convex portions 21 w and 22 w. When the first and second shutters 21 and 22 are closed, the convex portions 35 d and 36 d define a continuous ring 20 d that holds a portion of the disc 100 near the signal recording area thereof. The concave portion that is created between these two rings 20 w and 20 d defines the space 69 a. When the disc 100 is held thereon, the clamp area of the disc 100 is located right over the space 69 a.

[0597] Also, as shown in FIG. 143, the convex portion 36 d, second shutter 22 and disc supporting portion 25 a of the rotational member 25 are designed such that the space 69 b shown in FIG. 138 is provided under the disc 100 when the disc 100 is held on this disc cartridge 323. Although not shown in FIG. 143, the other convex portion 35 d and the first shutter 21 are also designed for the same purpose. Furthermore, the disc cartridge 323 is also designed such that a gap of 1 mm or more is provided between the disc 100 mounted and the first and second shutters 21 and 22. Also, the disc supporting portion 25 a is located outside of the space 69 b shown in FIG. 138 (i.e., under the side surfaces 59 a and 59 b that define the space 69 b) and does not obstruct the space 69 b at all.

[0598] By providing the space 69 b shown in FIG. 138 under the disc 100 in this manner, the signal recording area of the disc 100 stored in the disc cartridge 323 can be protected just as intended even if the disc 100 is pressed by the user too strongly.

[0599] It is to be noted that the disc cartridge 323 may be adapted to a disc 100 having a so-called “stack ring” or “stacking ring” in the vicinity of the clamp area 100 e′. As shown in FIG. 138, the stack ring is a protruding ring 100 p provided on the signal recording side 100A of the disc 100. The protruding ring 100 p has a circular shape coaxially formed with the center hole 100 h. The protruding ring 100 p prevents the signal recording area 100 d from contacting with a flat plane in the case where the disc is placed on the flat plane with the signal recording side 100A down. The protruding ring 100 p is located between the clamp area 100 e′ and the center hole 100 h and is apart from the edge of the center hole 100 h by 0.1 mm or more. The protruding ring 100 p has a width of about 1 mm in the radial direction and a height of 0.05 to 0.5 mm from the surface of the signal recording area 100 d. More specifically, in one type of the disc 100, a diameter of center hole 100 h is 15 mm, the clamp area 100 e′ is defined between a circle of a 22 mm diameter and a circle of a 33 mm diameter, the protruding ring 100 p is located in a region defined by a circle of a 17.5 mm diameter and a circle of a 22 mm diameter, the width of the protruding ring 100 p is about 1 mm, and the height the protruding ring 100 p is 0.3 mm or less. Alternatively, the protruding ring 100 p may be located between the clamp area 100 e′ and the signal recording area 100 d and is apart from the edge of the clamp area 100 e′ by 2 mm or less.

[0600] In this case, the disc holder 21 b of the first shutter 21 and the disc holders 22 a and 22 b of the second shutter 22 hold the disc 100 in such a manner as not to contact with neither a clamp area 100 e′ nor the protruding ring 100 p. Therefore, the space 69 a defined by the rings 20 w and 20 d is made enough large so as to include the protruding ring 100 p. More specifically, when the first and second shutters 21 and 22 are closed, the disc holder 21 b of the first shutter 21 and the disc holders 22 a and 22 b of the second shutter 22 hold the disc 100 in such a manner as not to contact with neither the clamp area 100 e′ nor the region which is located between the clamp area 100 e′ and the center hole 100 h and which is apart from the edge of the center hole 100 h by 0.1 mm or more, or in such a manner as not to contact with neither the clamp area 100 e′ nor the region which is located between the clamp area 100 e′ and the signal recording area 100 d and which is apart from the edge of the clamp area 100 e′ by 2 mm or less. In the case of the aforementioned specific type of the disc 100, the space 69 a should include the region defined by a first circle of the 17.5 mm diameter and a second circle which is smaller than the first circle by 0.1 to 0.3 mm. It is to be noted that the space 69 a may be continuous one region for the clamp area 100 e′ and the protruding ring 100 p or may be consist of separate regions for the clamp area 100 e′ and the protruding ring 100 p.

[0601] The disc cartridge 323 of this preferred embodiment further includes other structures that are specially designed to increase the mechanical strength of its members, selectively attach one of two types of disc stoppers, and increase the dustproofness, respectively, for the purpose of increasing the usefulness of this disc cartridge 323. Hereinafter, those structures will be described in detail.

[0602] First, the structure for increasing the mechanical strength of the members of the disc cartridge 323 will be described. As shown in FIGS. 142 and 144, while the first and second shutters 21 and 22 are closed, the disc holders 21 b, 22 a and 22 b apply an elastic force to the disc 100 toward the center thereof. This is because the connecting portion between the first shutter 21 and the disc holder 21 b and the connecting portions between the second shutter 22 and the disc holders 22 a and 22 b are deformed elastically by the disc 100.

[0603] However, if the user dropped the disc cartridge 323 by mistake or tried to rotate the disc 100 forcibly inside the disc cartridge 323 by applying a force onto the exposed side 100B of the disc 100, then a force could be applied from the center of the disc 100 to the disc holders 21 b, 22 a and 22 b outward. And if such a force were great enough, the connecting portion between the first shutter 21 and the disc holder 21 b and the connecting portions between the second shutter 22 and the disc holders 22 a and 22 b might be snapped. Among other things, the portion that connects the disc holder 21 b to the first shutter 21 and the portion that connects the disc holder 22 b to the second shutter 22 are too narrow to sufficiently resist the forces that are applied in the directions indicated by the arrows 21B and 22B, respectively, in FIG. 142.

[0604] In view of this potential snapping of those connecting portions, the sidewall 25 i of the rotational member 25 of this disc cartridge 323 is formed such that the cross sections 65 a and 65 b of its notches 25 g and 25 h are not parallel to the radial direction of the disc 100 (i.e., the directions 21B and 22B) but face the disc storage portion 100 d. Accordingly, while the shutters 21 and 22 are closed, the displacement of the disc holders 21 b and 22 b in the directions 21B and 22B is regulated by the cross sections 65 a and 65 b, respectively, so as not to exceed their predetermined limits.

[0605] By providing these cross sections 65 a and 65 b, the disc holders 21 b and 22 b would not be snapped off even if the user dropped the disc cartridge 323 by mistake or tried to move the disc holders 21 b and 22 b outward intentionally. Also, even if some force is applied in such a direction as to open the first and second shutters 21 and 22 accidentally while the shutters 21 and 22 are supposed to be closed, the disc holders 21 b and 22 b, which are going to move along with the shutters 21 and 22 being opened, will soon contact with the cross sections 65 a and 65 b, respectively. As a result, the first and second shutters 21 and 22 will not open accidentally. Thus, it is possible to minimize the unintentional movement of the first and second shutters 21 and 22 being closed.

[0606] Also, if the user attempts to open the first and second shutters 21 and 22 intentionally, then the first and second shutters 21 and 22 are going to rotate around the shaft holes 37 and 38, respectively, as shown in FIG. 142. Then, the inner sidewalls of the respective guide grooves 27 e and 28 f of the first and second shutters 21 and 22 are going to rotate the convex portions 25 e and 25 f of the rotational member 25 to the directions 25E and 25F around the shaft holes 37 and 38, respectively, as shown in FIG. 142.

[0607] In this case, if the ends of the guide grooves 27 e and 28 f were elongated in the directions 25E and 25F or if the guide grooves 27 e and 28 f allowed the convex portions. 25 e and 25 f to move in the directions 25E and 25F, respectively, then the first and second shutters 21 and 22 would move inconstantly.

[0608] To eliminate such an inconstant movement of the first and second shutters 21 and 22, those ends of the guide grooves 27 e and 28 f, where the convex portions 25 e and 25 f are located while the shutters 21 and 22 are closed, are elongated in the directions indicated by the arrows 27E and 28F, which substantially cross the arrows 25E and 25F at right angles. As shown in FIG. 142, the directions 27E and 28F are substantially parallel to the lines that connect the convex portions 25 e and 25 f to the shaft holes 37 and 38, respectively.

[0609] Furthermore, as shown in FIG. 144, the lower shell 11 is provided with a raised portion 33 b and the rotational member 25 is provided with a raised portion 25 w. The heights of these raised portions 33 b and 25 w are approximately equal to the thickness of the first and second shutters 21 and 22. The raised portion 33 b contacts with the back surface of the disc supporting portion 25 a of the rotational member 25. The raised portion 25 w engages with a concave portion 33 c that is formed on the inner lower surface 11 u of the cartridge body 10. These raised portions 33 b and 25 w are provided to support the portions of the rotational member 25 that are not in contact with the first or second shutter 21 or 22. Thus, even those portions of the rotational member 25 that are not in contact with the first or second shutter 21 or 22 would not be deformed or lose contact with the disc 100.

[0610] As already described for the fourteenth preferred embodiment, the disc holder 22 a includes the first and second portions 122 a and 222 a and the upper surface of the first portion 122 a is higher than that of the second portion 222 a. Also, the top of the first portion 122 a is inserted into a recessed portion 12 x that is provided on the back surface of the upper shell 12. The recessed portion 12 x is provided along a region where the top of the first portion 122 a passes as the shutters are going to be opened or closed.

[0611] As shown in FIGS. 142 and 144, the head opening 11 h is provided where the disc holder 22 a passes as the shutters are going to be opened or closed, and reaches a side surface of the lower shell 11. Accordingly, when the cartridge body is formed by combining the lower and upper shells 11 and 12 together, the mechanical strength of the cartridge body around the head opening 11 h should be secured only by the upper shell 12.

[0612] In the disc cartridge 323, as the shutters are going to be closed, the first portion 122 a of the disc holder 22 a can grip the disc 100 thereon just as intended as already described for the fourteenth preferred embodiment. Also, since the upper surface of the second portion 222 a of the disc holder 22 a is located at a low vertical level, the upper shell 12 does not have to have a reduced thickness over the second portion 222 a. Accordingly, the recessed region 12 x of the upper shell 12, where the first portion 122 a of the disc holder 22 a passes as the shutters are going to be opened or closed, should have a reduced thickness but can be just a small portion of the overall upper shell 12. Thus, it is possible to prevent the mechanical strength of the overall cartridge body from decreasing excessively around the head opening 11 h.

[0613] Furthermore, the disc cartridge 323 of this preferred embodiment has a structure of increasing the rigidity thereof while the shutters are closed as described for the thirteenth preferred embodiment.

[0614] Specifically, as shown in FIGS. 145 and 146, the first and second shutters 21 and 22 have two pairs of contact portions 21 f′, 22 f′ and 21 g′, 22 g′, which are discontinuous and separated from each other by the hole 20 h and each pair of which overlaps with each other vertically. That is to say, the first shutter 21 includes the contact portions 21 g′ and 21 f′, while the second shutter 22 includes the contact portions 22 g′ and 22 f′. FIGS. 146A and 146B are cross-sectional views of the first and second shutters 21 and 22 as viewed along the lines N-N and O-O shown in FIG. 145, respectively. In one pair of contact portions 21 g′ and 22 g′ shown in FIG. 146A, while the shutters 21 and 22 are closed, the contact portion 21 g′ of the first shutter 21 is located over the contact portion 22 g′ of the second shutter 22 in the thickness direction of the shutters 21 and 22. In the other pair of contact portions 21 f′ and 22 f′ shown in FIG. 146B, while the shutters 21 and 22 are closed, the contact portion 21 f′ of the first shutter 21 is located under the contact portion 22 f′ of the second shutter 22 in the thickness direction of the shutters 21 and 22.

[0615] Also, as shown in FIG. 146A, the edge of the contact portion 22 g′ of the second shutter 22 includes a convex portion 38 c that extends along the contact portion 22 g′. On the other hand, the first shutter 21 includes a concave portion 37 a that engages with the convex portion 38 c while the shutters 21 and 22 are closed.

[0616] Furthermore, as shown in FIG. 147, where the disc holder 22 a of the second shutter 22 contacts with the convex portion 27 a of the first shutter 21, the convex portion 27 a includes a protrusion 37 a and the disc holder 22 a includes a concave portion 38 a that engages with the protrusion 37 a. Another concave portion 37 b is provided over the protrusion 37 a. Another protrusion 38 b, which engages with the concave portion 37 b, is provided over the concave portion 38 a. The protrusion 37 a and the concave portion 37 b define another contact portion 37 e of the first shutter 21. On the other hand, the concave portion 38 a and the protrusion 38 b define another contact portion 38 e of the second shutter 22. These contact portions 37 e and 38 e of the first and second shutters 21 and 22 will be herein referred to as a “third pair of contact portions”.

[0617] As described above, in the disc cartridge 323 of the twenty-third preferred embodiment, two separate pairs of contact portions 21 g′, 22 g′ and 21 f′, 22 f′ are provided for the first and second shutters 21 and 22 and each pair of contact portions of the first and second shutters 21 and 22 overlaps with each other in the thickness direction of the shutters. Also, the order in which the contact portions 21 g′ and 22 g′ of the first pair overlap with each other is reverse to the order in which the contact portions 21 f′ and 22 f′ of the second pair overlap with each other. By utilizing such a structure, the first and second shutters 21 and 22 closed will not be raised unintentionally, and the contact portions thereof can have increased rigidity.

[0618] Also, by providing the concave portion 37 c and the convex portion 38 c for the contact portions 21 g′ and 22 g′ of the first and second shutters 21 and 22, respectively, the contact portions 21 g′ and 22 g′ of the shutters 21 and 22 closed will not be easily disengaged from each other due to the inconstant movement thereof, for example. In this manner, the first and second shutters 21 and 22 can contact with each other even more closely, thus increasing the dustproofness of the disc cartridge around these contact portions of the shutters.

[0619] Furthermore, by providing the third pair of contact portions 37 e and 38 e for the first and second shutters 21 and 22, respectively, the contact portions of the first and second shutters 21 and 22 closed can have increased rigidity. Also, the contact portion 21 g′ and the protrusion 37 a of the first shutter 21 are sandwiched between the protrusion 38 b and the contact portion 22 g′ of the second shutter 22. As a result, the contact portions of the first and second shutters 21 and 22 closed can have further increased rigidity.

[0620] Next, the structure that is specially designed to selectively attach one of two types of disc stoppers to the disc cartridge 323 will be described. As shown in FIG. 144, the upper shell 12 of the disc cartridge 323 includes the shaft hole 12 m and another hole 12 m′. Either the disc stopper 55 or a disc stopper 59 can be fitted in the holes 12 m and 12 m′ as a means for preventing the disc 100 from dropping down through the disc window 12 w. The disc stopper 55 of the disc cartridge 323 of this twenty-third preferred embodiment has the same structure as the disc stopper 55 of the disc cartridge 321 of the twenty-first preferred embodiment described above. That is to say, by inserting the shaft 55 a into, and engaging it with, the shaft hole 12 m of the upper shell 12, the disc stopper 55 can rotate on the shaft 55 a. Then, as already described for the twenty-first preferred embodiment, a portion of the disc stopper 55 may be protruded into the disc window 12 w, thereby preventing the disc 100 from dropping accidentally. Alternatively, if the disc stopper 55 is rotated to the position shown in FIG. 125, the disc 100 may be removed from the disc cartridge 323.

[0621] On the other hand, the disc stopper 59 includes protrusions 59 a and 59 b. When the disc stopper 59 is attached to the upper shell 12, the protrusions 59 a and 59 b of the disc stopper 59 are inserted into, and engaged with, the holes 12 m and 12 m′, respectively. Since the disc stopper 59 is fixed onto the upper shell 12 at these two points, the disc stopper 59 is not rotatable but always protrudes partially into the disc window 12 w. That is to say, while the disc stopper 59 is attached to the upper shell 12, the disc 100 stored in the disc cartridge 323 is not removable.

[0622] In this manner, by providing the shaft hole 12 m and the hole 12 m′, which may be engaged with either the disc stopper 55 or the disc stopper 59, as engaging means for the upper shell 12, one of these two disc stoppers 55 and 59 may be selectively attached to the cartridge body depending on the necessity. That is to say, by adopting one of these two disc stoppers 55 and 59 selectively, the resultant disc cartridge 323 may or may not allow the user to remove the disc 100 that has been once stored in the disc cartridge 323.

[0623] The disc cartridge 323 shown in FIG. 144 is illustrated as not including the removal history hole 11 n or the cap member 56 of the disc cartridge 321 of the twenty-first preferred embodiment. However, the removal history hole 11 n and cap member 56 may be provided for the disc cartridge 323. If the removal history hole 11 n, cap member 56 and disc stopper 55 are provided for the disc cartridge 323, then the cap member 56 will drop off as already described for the twenty-first preferred embodiment as the disc stopper 55 is rotated to remove the disc 100 from the disc cartridge 323. Then, the removal history hole 11 n will be fully exposed. On the other hand, if the disc stopper 59 is attached to the upper shell 12 instead of the disc stopper 55, then the disc 100 cannot be removed by rotating the disc stopper 59. Accordingly, in that case, the removal history hole 11 n will be kept covered with the cap member 56.

[0624] Next, the structure of increasing the dustproofness of the disc cartridge 323 will be described with reference to FIGS. 144, 145, 148 and 149. As shown in FIG. 144, the chucking and head openings 11 c and 11 h of the lower shell 11 are surrounded with a rim 33 a, which is indicated by the dashed lines in FIG. 145. FIG. 148 is a cross-sectional view of the disc cartridge 323 as viewed along the line M-M shown in FIG. 145. As shown in FIG. 148, the back surfaces of the first and second shutters 21 and 22 include concave portions 37 d and 38 d, respectively, which engage with the rim 33 a.

[0625] The first and second shutters 21 and 22 rotate on the lower shell 11. Accordingly, as the first and second shutters 21 and 22 rotate, the dust that has been deposited on the back surfaces of the first and second shutters 21 and 22 would easily enter the cartridge body if there was a gap between the first and second shutters 21 and 22 and the lower shell 11. However, by filling the gap with this structure, almost no dust will enter the disc cartridge 323 from the chucking and head openings 11 c and 11 h.

[0626] Furthermore, as shown in FIG. 149, the contact portions of the first and second shutters 21 and 22 around the hole 20 h, which is defined by the first and second shutters 21 and 22 closed, are provided with mutually engaging concave and convex portions 35 a, 36 a and 35 b, 36 b. That is to say, the first shutter 21 includes the concave portions 35 a and 35 b and the second shutter 22 includes the convex portions 36 a and 36 b. The convex portions 36 a and 36 b of the second shutter 22 protrude from the contact plane that is defined by the first and second shutters 21 and 22 closed. Thus, no dust will enter the disc cartridge 323 from the hole 20 h and through the contact plane between the first and second shutters 21 and 22.

[0627] In the twenty-third preferred embodiment described above, the disc supporting portion 25 a for holding the disc 100 thereon is provided for the rotational member 25 to define the space 69 b shown in FIG. 138 under the disc 100. Alternatively, any other structure may be adopted to define the space 69 b shown in FIG. 138 under the disc 100. For example, as shown in FIG. 150, a disc supporting portion 25 a′ for holding the outer edge of the disc 100 may be provided for an alternative upper shell 12′. Even so, by forming the disc supporting portion 25 a′ and first and second shutters 21 and 22 in such shapes as to define the space 69 b shown in FIG. 138 under the disc 100, the signal recording area of the disc 100 will not contact with the shutters or disc supporting portion of the disc cartridge even if the disc 100 is pressed by the user too strongly.

[0628] Embodiment 24

[0629] Hereinafter, a disc drive according to a twenty-fourth specific preferred embodiment of the present invention will be described with reference to FIG. 151.

[0630]FIG. 151 is perspective view schematically illustrating a main portion of a disc drive 900 according to the twenty-fourth preferred embodiment. Any of the disc cartridges 301 through 323 according to the first through twenty-third preferred embodiments of the present invention described above may be loaded into this disc drive 900. In the specific example illustrated in FIG. 151, the disc cartridge 323 according to the twenty-third preferred embodiment is loaded into this disc drive 900. In FIG. 151, the disc 100 is indicated by the dashed line.

[0631] As shown in FIG. 151, the disc drive 900 includes: a driver 902 for rotating the disc 100 that is stored inside the disc cartridge 323; and a head 908 for reading and/or writing a signal (or information) from/on the disc 100.

[0632] The driver 902 includes a spindle motor 904 and a turntable 906 that is fitted with the shaft of the spindle motor 904. The spindle motor 904 is supported on a base 910. The head 908 is moved by an actuator (not shown) along a guide shaft 912.

[0633] The disc drive 900 further includes a damper 916 that is supported by an arm 914. Each of the turntable 906 and the damper 916 includes a magnet and a magnetic body, for example. As will be described later, the disc 100 is sandwiched and held between the damper 916 and the turntable 906 by utilizing the attraction between the magnets, and thereby mounted onto the turntable 906. In this manner, the driving force of the spindle motor 904 can be transmitted to the disc 100 just as intended and the disc 100 can be rotated without fluttering.

[0634] The disc cartridge 323 includes the opener/closer 25 j for opening and closing the first and second shutters 21 and 22 on its side surface 10 r that is parallel to the direction 1A in which the disc cartridge 323 is inserted into this disc drive 900. To operate this opener/closer 25 j, the disc drive 900 includes a shutter opening/closing mechanism 918 that engages with the opener/closer 25 j to open and close the shutters 21 and 22. The shutter opening/closing mechanism 918 is provided near the side surface 10 r of the disc cartridge 323 that has been loaded into the disc drive 900. In FIG. 151, to illustrate the opener/closer 25 j clearly, the shutter opening/closing mechanism 918 is illustrated as being separated from the opener/closer 25 j. An actuator for use to move the shutter opening/closing mechanism 918 is not illustrated in FIG. 151, either.

[0635] It should be noted that the shutter opening/closing mechanism 918 needs to be located beside the shutter opener/closer of the disc cartridge to be inserted into this disc drive 900. For example, if the disc cartridge to be loaded has a shutter opener/closer on the side surface lop including the head opening 11 h as in the first or tenth preferred embodiment described above, then the shutter opening/closing mechanism 918 should be provided near the side surface 10 p. On the other hand, when the disc cartridge according to any of the sixteenth through eighteenth preferred embodiments described above is loaded into the disc drive 900, the shutter opening/closing mechanism 918 may be provided near the side surface 10 q.

[0636] Optionally, two or more shutter opening/closing mechanisms 918 may be provided for the same disc drive 900. For example, a second shutter opening/closing mechanism 918 may be additionally provided near the side surface 10 p of the disc cartridge 323 shown in FIG. 151 so that either the disc cartridge 301 of the first preferred embodiment or the disc cartridge 323 of the twenty-third preferred embodiment may be loaded into this disc drive 900.

[0637] The shutter opening/closing mechanism 918 has such a structure as to engage with the opener/closer 25 j of the disc cartridge. In the disc cartridge 323, the first and second shutters 21 and 22 are opened or closed by sliding the opener/closer 25 j. Accordingly, the shutter opening/closing mechanism 918 should engage with the opener/closer 25 j and slide in the direction indicated by the arrow 1A. Where the opener/closer 25 j has a gear shape (i.e., when a disc cartridge having a geared opener/closer is loaded as in the sixteenth preferred embodiment), the shutter opening/closing mechanism 918 also needs to have a gear shape.

[0638] Posts 920 are provided on the base 910 to define a vertical level at which the disc cartridge 323 is supported. That is to say, the disc cartridge 323 is supported on the top of the posts 920. Also, positioning pins 922 are further provided on the base 910 so as to engage with the positioning holes 11 w of the disc cartridge 323.

[0639] These posts 920 and positioning pins 922 function as a supporting structure for disposing the disc cartridge 323 at a predetermined position with respect to the driver 902. Optionally, instead of the posts 920 and the positioning pins 922, a tray may be provided as an alternative supporting structure for the disc drive 900. In that case, the tray may be drawn out to mount the disc cartridge 323 thereon and then inserted into the disc drive 900 to load the disc 100 into the disc drive 900 and to dispose the disc cartridge 323 at a predetermined position with respect to the driver 902 and the head 908. As another alternative, the tray and the positioning pins 922 may be used in combination as the supporting structure.

[0640] Hereinafter, it will be described how this disc drive 900 operates.

[0641] First, the disc cartridge 323 that stores the disc 100 therein is loaded into the disc drive 900. The disc cartridge 323 may be loaded either manually by the user or automatically by a loading mechanism (not shown). In the latter case, the loading mechanism may transport the disc cartridge 323 from a disc cartridge insert slot (not shown) of the disc drive 900 to the position illustrated in FIG. 151. Then, the concave portions 10 c or 10 e as described above for the first or sixteenth preferred embodiment may be provided at the positions indicated by the arrows 926 in FIG. 151 and may be engaged with the loading mechanism. Alternatively, the tray may also be used as described above. In one of these methods, the disc cartridge 323 is disposed at a predetermined position with respect to the driver 902 and the head 908.

[0642] As another alternative, the concave portion 10 g as described above for the first preferred embodiment or the slit 10 b as described above for the sixteenth preferred embodiment may be provided at the position of the disc cartridge 323 as indicated by the arrow 928 or 930 in FIG. 151. In that case, the disc drive 900 may have a convex portion (not shown) that engages with the concave portion 10 g or the slit 10 b. Then, even if the user tries to insert the disc cartridge 323 upside down or the wrong way round into this disc drive 900, the disc cartridge 323 is ejected because interference should occur between the disc cartridge 323 and the disc drive 900. In this manner, it is possible to prevent the user from inserting the disc cartridge 323 into the disc drive 900 erroneously.

[0643] When the disc cartridge 323 is disposed at the position shown in FIG. 151, the shutter opening/closing mechanism 918 engages with the opener/closer 25 j, thereby sliding the opener/closer 25 j in the direction opposite to that indicated by the arrow 1A. As a result, the first and second shutters 21 and 22 start to open to expose the head and chucking openings 11 h and 11 c in the end. Also, as already described for the twentieth preferred embodiment, the shutter opening/closing mechanism 918 makes the disc holders 21 b, 22 a and 22 b release the disc 100 by way of the first and second shutters 21 and 22. Thus, the disc 100 is released from the disc holders 21 b, 22 a and 22 b. Subsequently, the arm 914 holding the damper 916 thereon lowers, thereby sandwiching and holding the disc 100 between the damper 916 and the turntable 906. Consequently, the disc 100 is mounted on the turntable 906 so as to be rotatable inside the disc storage portion of the disc cartridge 323.

[0644] Next, the disc 100 starts being rotated by the spindle motor 904. Then, the head 908 accesses the signal recording area of the disc 100 to read or write a signal from/on the disc 100.

[0645] To unload the disc cartridge 323 from the disc drive 900, first, the arm 914 is raised, thereby separating the damper 916 from the disc 100. Next, the shutter opening/closing mechanism 918 is moved in the direction indicated by the arrow 1A to slide the opener/closer 25 j. As a result, the first and second shutters 21 and 22 are closed. As the first and second shutters 21 and 22 are going to be closed, the disc holders grip the disc 100 thereon. And when the first and second shutters 21 and 22 are completely closed, the disc holders hold the disc 100 thereon. Thereafter, an unloading mechanism (not shown) ejects the disc cartridge 323 from the disc drive 900.

[0646] Into the disc drive 900 shown in FIG. 151, the disc cartridge 323 is loaded horizontally. Alternatively, as already described for the first or eighth preferred embodiment, the disc drive 900 may also be mounted vertically so that the disc cartridge is loaded thereto vertically. This is because even when the disc cartridge is loaded vertically into the disc drive 900, the disc stoppers still can prevent the disc 100 from dropping down from the disc storage portion.

[0647] In the first through twenty-third preferred embodiments described above, a nonwoven fabric is ultrasonic welded or adhered to the shutters. However, if the disc has some anti-scratching structure (e.g., if the signal recording side of the disc is covered with a stiff hard coating), then the nonwoven fabric does not have to be attached thereto, but the shutters may directly contact with the disc. Also, not the entire surface of the shutters has to contact with the signal recording side of the disc, but the shutters may have such a structure that at least portion of the shutters contacts with the signal recording side of the disc. That is to say, not the entire surface but just a portion of the surface of the shutters may be in contact with the disc. In that case, some anti-scratching structure (e.g., a nonwoven fabric) may be provided for only that portion contacting with the disc.

[0648] In the first through twenty-fourth preferred embodiments of the present invention described above, the disc 100 to be stored in the disc cartridge has just one signal recording side 100A. However, a single-sided disc like this is herein adopted for illustrative purposes only. This is because the disc cartridge of the present invention has such a structure as to expose one side of the disc stored therein and because a single-sided disc is best suited to the disc cartridge of that type. Thus, even a disc having two signal recording sides (i.e., a double-sided disc) may be appropriately stored in the disc cartridge of the present invention and may be loaded into a disc drive to read or write a signal therefrom/thereon. It should be noted, however, that where a double-sided disc is stored in the disc cartridge of the present invention, dust may be deposited on the exposed one of the two signal recording sides. Accordingly, in that case, some mechanism for preventing the unwanted dust deposition should be provided for the disc cartridge.

[0649] Also, in the first through twenty-fourth preferred embodiments described above, the size of the disc 100 is not particularly specified. This is because the disc cartridge of the present invention may accommodate a disc having a size of 12 cm or any of various other sizes.

[0650] Furthermore, in the first through twenty-fourth preferred embodiments described above, the disc cartridge is illustrated as having an outer dimension that is slightly greater than the size of the disc. However, the size relationship between the disc and the disc cartridge is not limited to the illustrated one. For example, even when the disc cartridge has an outer dimension that is large enough to store a 12 cm disc therein, the disc storage portion and the disc holders of the disc cartridge may have their sizes and structures defined in such a manner as to store an 8 cm disc. Such a disc cartridge may be used as an adapter for getting read and write operations performed on an 8 cm disc by a disc drive for a 12 cm disc.

[0651] The various features of the present invention as described for the first through twenty-fourth preferred embodiments may be combined appropriately. For example, the rotation stoppers as described for the nineteenth preferred embodiment may be provided for the disc cartridge of the sixteenth preferred embodiment. Also, the recesses for use to collect dust therein as described for the fifteenth preferred embodiment may be provided for the disc cartridge of the sixteenth preferred embodiment. As can be seen, the first through twenty-fourth preferred embodiments of the present invention may be modified or combined in numerous other ways and not all of those possible combinations or alternatives have been described herein. However, it is quite possible for those skilled in the art to conceive and carry out those various alternatives or combinations by reference to the description of the present application. Thus, it is intended by the appended claims to cover all of those modifications or combinations of the present invention that fall within the true spirit and scope of the present invention.

INDUSTRIAL APPLICABILITY

[0652] The disc cartridge according to various preferred embodiments of the present invention described above can be used particularly effectively to store a disc having only one signal recording side. The cartridge body of the disc cartridge has such a structure as to cover only the signal recording side of the disc and expose the other side thereof. Thus, the disc cartridge can have a reduced thickness. Also, the shutters of the disc cartridge are formed in such a shape as to cover the openings on just one side of the disc cartridge. Accordingly, the shutters can have a simplified structure and can be formed at a lower cost. In addition, the disc holders of the disc cartridge hold a disc thereon by pressing the disc against the shutters or the cartridge body. Thus, the disc will not move inconstantly inside the cartridge body and no dust will be deposited on the signal recording side of the disc. Furthermore, since the label side of the disc is displayed inside the disc window, the disc cartridge can also have a good design.

[0653] Thus, the present invention provides a thinner and highly dustproof disc cartridge of a good design that is applicable for use in various types of disc drives.

[0654] It should be understood that the foregoing description is only illustrative of the invention. Various alternatives and modifications can be devised by those skilled in the art without departing from the invention. Accordingly, the present invention is intended to embrace all such alternatives, modifications and variances which fall within the scope of the appended claims. 

1. A disc cartridge comprising: a cartridge body including a disc storage portion, a chucking opening and a head opening, wherein the disc storage portion has a disc window and a bottom and stores a disc, having first and second sides, therein so that the disc is rotatable in the disc storage portion and that the first side of the disc is exposed inside the disc window; the chucking opening is formed on the bottom of the disc storage portion so as to get the disc chucked externally; and the head opening is also formed on the bottom of the disc storage portion so as to allow a head, which reads and/or writes a signal from/on the second side of the disc, to access the second side of the disc; first and second shutters, provided on the bottom of the disc storage portion, for exposing or covering the head opening; and a rotational member, which is provided over the first and second shutters inside the disc storage portion and which rotates as the first and second shutters are opened or closed, wherein the rotational member includes: a disc supporting portion, which contacts with an outer periphery of the second side of the disc while the first and second shutters are closed and thereby holds the disc thereon; and a notch, which is provided for the disc supporting portion so as to be located inside the head opening while the first and second shutters are opened, and wherein the disc storage portion includes a sidewall along an outer periphery of the bottom, and wherein the first and second shutters include disc holders for holding the disc thereon with the center of the disc offset from the center of the disc storage portion such that an outer side surface of the disc contacts with the sidewall of the disc storage portion at a position where the notch of the rotational member is located while the first and second shutters are closed, and wherein the inner circumference of a region, in which the disc supporting portion of the rotational member contacts with the second side of the disc, defines a circle that has its center offset from the center of the disc storage portion.
 2. The disc cartridge of claim 1, wherein while the first and second shutters are closed, the center of the disc is aligned with the center of the circle.
 3. The disc cartridge of claim 1, wherein while the first and second shutters are closed, a distance between the center of the disc and the center of the disc storage portion is about 0.5 mm to about 1.5 mm.
 4. The disc cartridge of claim 2, wherein a portion of the sidewall of the disc storage portion, which contacts with the outer side surface of the disc, has a radius of curvature that is substantially equal to that of the disc.
 5. The disc cartridge of claim 2, wherein a portion of the sidewall of the disc storage portion, which does not contact with the outer side surface of the disc, has a radius of curvature that is greater than that of the disc.
 6. A disc cartridge comprising: a cartridge body including a disc storage portion, a chucking opening and a head opening, wherein the disc storage portion has a disc window and a bottom and stores a disc, having first and second sides, therein so that the disc is rotatable in the disc storage portion and that the first side of the disc is exposed inside the disc window; the chucking opening is formed on the bottom of the disc storage portion so as to get the disc chucked externally; and the head opening is also formed on the bottom of the disc storage portion so as to allow a head, which reads and/or writes a signal from/on the second side of the disc, to access the second side of the disc; first and second shutters, provided on the bottom of the disc storage portion, for exposing or covering the head opening; and a rotational member, which is provided over the first and second shutters inside the disc storage portion and which rotates as the first and second shutters are opened or closed, wherein the rotational member includes: a disc supporting portion, which contacts with an outer periphery of the second side of the disc while the first and second shutters are closed and thereby holds the disc thereon; and a notch, which is provided for the disc supporting portion so as to be located inside the head opening while the first and second shutters are opened, and wherein the disc storage portion includes a sidewall along an outer periphery of the bottom, and wherein one of the first and second shutters includes a disc holder for applying an elastic force to the disc and holding the disc thereon such that an outer side surface of the disc contacts with the sidewall of the disc storage portion at a position where the notch of the rotational member is located while the first and second shutters are closed, and wherein the elastic force is applied to the disc by deforming elastically the first or second shutter that includes the disc holder.
 7. The disc cartridge of claim 6, wherein the cartridge body includes a recessed portion on the bottom of the disc storage portion, and wherein the first or second shutter that includes the disc holder is deformed elastically near a sidewall that defines the recessed portion.
 8. A disc cartridge comprising: a cartridge body including a disc storage portion, a chucking opening and a head opening, wherein the disc storage portion has a disc window and a bottom and stores a disc, having first and second sides, therein so that the disc is rotatable in the disc storage portion and that the first side of the disc is exposed inside the disc window; the chucking opening is formed on the bottom of the disc storage portion so as to get the disc chucked externally; and the head opening is also formed on the bottom of the disc storage portion so as to allow a head, which reads and/or writes a signal from/on the second side of the disc, to access the second side of the disc; a shutter, provided on the bottom of the disc storage portion, for exposing or covering the head opening; and a disc stopper, which has an arched concave side surface and which is supported by the cartridge body so as to be movable from a first position, at which the arched concave side surface protrudes over the disc that is stored inside the disc storage portion, to a second position, at which the arched concave side surface is not located over the discs, or vice versa.
 9. The disc cartridge of claim 8, wherein the arched concave side surface of the disc stopper extends along a longer side of the disc stopper, and wherein the disc stopper moves from the first position to the second position, or vice versa, by sliding vertically to the longer side with respect to the cartridge body.
 10. The disc cartridge of claim 8, wherein the arched concave side surface of the disc stopper extends along a longer side of the disc stopper, and wherein the disc stopper moves from the first position to the second position, or vice versa, by rotating on a shaft that extends parallelly to the longer side.
 11. The disc cartridge of claim 8, wherein the arched concave side surface of the disc stopper extends along a longer side of the disc stopper, and wherein the disc stopper moves from the first position to the second position, or vice versa, by rotating on a shaft substantially parallelly to the first side of the disc, the shaft being provided near one end of the longer side of the disc stopper.
 12. The disc cartridge of claim 11, wherein the other end of the longer side of the disc stopper is engaged with the cartridge body.
 13. A disc cartridge comprising: a cartridge body including a disc storage portion, a chucking opening and a head opening, wherein the disc storage portion has a disc window and a bottom and stores a disc, having first and second sides, therein so that the disc is rotatable in the disc storage portion and that the first side of the disc is exposed inside the disc window; the chucking opening is formed on the bottom of the disc storage portion so as to get the disc chucked externally; and the head opening is also formed on the bottom of the disc storage portion so as to allow a head, which reads and/or writes a signal from/on the second side of the disc, to access the second side of the disc; a shutter, provided on the bottom of the disc storage portion, for exposing or covering the head opening; a removal history hole, which is provided for the cartridge body; a cap member, which covers the removal history hole at least partially; and a disc stopper, which is supported by the cartridge body so as to be movable from a first position, at which the disc stopper protrudes over the disc that is stored inside the disc storage portion, to a second position, at which the disc stopper is not located over the disc, or vice versa, wherein while the disc stopper is moving from the first position to the second position, the disc stopper removes the cap member from the removal history hole.
 14. The disc cartridge of claim 13, wherein the disc stopper moves from the first position to the second position, or vice versa, by rotating on a shaft substantially parallelly to the first side of the disc, the shaft being provided near one end of the longer side of the disc stopper thereof, and wherein the center of rotation of the disc stopper is aligned with the center of the removal history hole.
 15. The disc cartridge of claim 14, wherein the cap member has a columnar shape and includes: connectors that are connected to an inner sidewall of the removal history hole and a convex portion to engage with the disc stopper, the disc stopper including a concave portion that engages with the convex portion of the cap member.
 16. The disc cartridge of claim 15, wherein the center of the concave portion of the disc stopper is aligned with the center of rotation of the disc stopper, and wherein by rotating the disc stopper, the cap member is rotated, the connectors are snapped off, and the cap member drops off from the removal history hole.
 17. A disc cartridge comprising: a cartridge body including a disc storage portion, a chucking opening and a head opening, wherein the disc storage portion has a disc window and a bottom and stores a disc, having first and second sides, therein so that the disc is rotatable in the disc storage portion and that the first side of the disc is exposed inside the disc window; the chucking opening is formed on the bottom of the disc storage portion so as to get the disc chucked externally; and the head opening is also formed on the bottom of the disc storage portion so as to allow a head, which reads and/or writes a signal from/on the second side of the disc, to access the second side of the disc; first and second shutters, provided on the bottom of the disc storage portion, for exposing or covering the head opening; a rotational member, which is provided over the first and second shutters inside the disc storage portion and which is interlocked with the first and second shutters in such a manner as to open or close the first and second shutters when rotates inside the disc storage portion; and a disc holder for holding the disc thereon so as not to contact with a signal recording area on the second side of the disc while the first and second shutters are closed.
 18. The disc cartridge of claim 17, wherein supposing that a distance from the center of the disc to a first point on the second side of the disc is Rin, where the first point is located closer to the center of the disc than, and defined near, the inner periphery of the signal recording area while the first and second shutters are closed; a distance from the center of the disc to a second point on the second side of the disc is Rout, where the second point is located closer to an outer edge of the disc than, and defined near, the outer periphery of the signal recording area while the first and second shutters are closed; a space having a height S needs to be provided under the second side of the disc; a first circle having a radius of Rout is defined on the second side of the disc; a second circle having a radius of (Rout—1.2 S) is defined on a plane that is separated from the second side by a distance of 0.3 S and parallel to the second side; and a third circle having a radius of (Rout—16.2 S) is defined on a plane that is separated from the second side by the distance S and parallel to the second side, the space is obtained by removing a circular cylinder, having a bottom radius of Rin as measured from the center of the disc and the height S, from first and second truncated cones, where the bottom and top of the first truncated cone are defined by the first and second circles, respectively, and the bottom and top of the second truncated cone are defined by the second and third circles, respectively.
 19. The disc cartridge of claim 18, wherein the height S of the space is 1 mm, the radius Rin of the bottom of the circular cylinder is 20 mm, and the radius Rout of the first circle is 59 mm.
 20. The disc cartridge of claim 18, wherein the otational member includes: a disc supporting portion, which contacts with an outer periphery of the second side of the disc while the first and second shutters are closed and thereby holds the disc thereon; and a notch, which is provided for the disc supporting portion so as to be located inside the head opening while the first and second shutters are opened, and wherein the disc storage portion includes a sidewall along an outer periphery of the bottom, and wherein the disc holder holds the disc thereon with the center of the disc offset from the center of the disc storage portion such that an outer side surface of the disc contacts with the sidewall of the disc storage portion at a position where the notch of the rotational member is located while the first and second shutters are closed.
 21. The disc cartridge of claim 20, wherein the disc supporting portion of the rotational member is located at such a position as not to obstruct the space while the first and second shutters are closed.
 22. The disc cartridge of claim 20, wherein the inner circumference of a region, in which the disc supporting portion of the rotational member contacts with the second side of the disc, defines a circle that has its center offset from the center of the disc storage portion.
 23. The disc cartridge of claim 22, wherein while the first and second shutters are closed, the center of the disc is aligned with the center of the circle.
 24. The disc cartridge of claim 22, wherein while the first and second shutters are closed, a distance between the center of the disc and the center of the disc storage portion is about 0.5 mm to about 1.5 mm.
 25. A disc cartridge comprising: a cartridge body including a disc storage portion, a chucking opening and a head opening, wherein the disc storage portion has a disc window and a bottom and stores a disc, having first and second sides, therein so that the disc is rotatable in the disc storage portion and that the first side of the disc is exposed inside the disc window; the chucking opening is formed on the bottom of the disc storage portion so as to get the disc chucked externally; and the head opening is also formed on the bottom of the disc storage portion so as to allow a head, which reads and/or writes a signal from/on the second side of the disc, to access the second side of the disc; first and second shutters, provided on the bottom of the disc storage portion, for exposing or covering the head opening; a rotational member, which is provided over the first and second shutters inside the disc storage portion and which is interlocked with the first and second shutters in such a manner as to open or close the first and second shutters when rotates inside the disc storage portion; and a disc holder for holding the disc thereon in such a manner as not to contact with a clamp area, which is provided on the second side of the disc, while the first and second shutters are closed.
 26. A disc cartridge comprising: a cartridge body including a disc storage portion, a chucking opening and a head opening, wherein the disc storage portion has a disc window and a bottom and stores a disc, having first and second sides, therein so that the disc is rotatable in the disc storage portion and that the first side of the disc is exposed inside the disc window; the chucking opening is formed on the bottom of the disc storage portion so as to get the disc chucked externally; and the head opening is also formed on the bottom of the disc storage portion so as to allow a head, which reads and/or writes a signal from/on the second side of the disc, to access the second side of the disc; first and second shutters, provided on the bottom of the disc storage portion, for exposing or covering the head opening; and a rotational member, which is provided over the first and second shutters inside the disc storage portion and which is interlocked with the first and second shutters in such a manner as to open or close the first and second shutters when rotates inside the disc storage portion, wherein the first and second shutters have first and second pairs of contact portions in two separate regions, the contact portions of each of the first and second pairs contacting and overlapping with each other in a thickness direction, an order in which the contact portions of the first pair overlap with each other being reverse to an order in which the contact portions of the second pair overlap with each other.
 27. The disc cartridge of claim 20, wherein the first and second shutters further include a sidewall, which stands in the vicinity of the first pair of contact portions, and a third pair of contact portions, which contacts and overlaps with each other in the thickness direction over the sidewall, one of the two contact portions of the first pair and one of the two contact portions of the third pair of the first or second shutter contacting with, and sandwiching, the other contact portion of the first pair and the other contact portion of the third pair of the second or first shutter.
 28. A disc cartridge comprising: a cartridge body including a disc storage portion, a chucking opening and a head opening, wherein the disc storage portion has a disc window and a bottom and stores a disc, having first and second sides, therein so that the disc is rotatable in the disc storage portion and that the first side of the disc is exposed inside the disc window; the chucking opening is formed on the bottom of the disc storage portion so as to get the disc chucked externally; and the head opening is also formed on the bottom of the disc storage portion so as to allow a head, which reads and/or writes a signal from/on the second side of the disc, to access the second side of the disc; first and second shutters, provided on the bottom of the disc storage portion, for exposing or covering the head opening; and a rotational member, which is provided over the first and second shutters inside the disc storage portion and which is interlocked with the first and second shutters in such a manner as to open or close the first and second shutters when rotates inside the disc storage portion, wherein the first and second shutters closed contact with each other to define a hole in a region corresponding to a center hole of the disc, and wherein a contact portion of one of the first and second shutters includes a convex portion around the hole, while a contact portion of the other shutter includes a concave portion, which engages with the convex portion, around the hole.
 29. A disc cartridge comprising: a cartridge body including a disc storage portion, a chucking opening and a head opening, wherein the disc storage portion has a disc window and a bottom and stores a disc, having first and second sides, therein so that the disc is rotatable in the disc storage portion and that the first side of the disc is exposed inside the disc window; the chucking opening is formed on the bottom of the disc storage portion so as to get the disc chucked externally; and the head opening is also formed on the bottom of the disc storage portion so as to allow a head, which reads and/or writes a signal from/on the second side of the disc, to access the second side of the disc; first and second shutters, provided on the bottom of the disc storage portion, for exposing or covering the head opening; and a rotational member, which is provided over the first and second shutters inside the disc storage portion and which is interlocked with the first and second shutters in such a manner as to open or close the first and second shutters when rotates inside the disc storage portion, wherein the first and second shutters include a plurality of disc holders that contacts with an outer side surface of the disc and its surround portions and that holds the disc thereon while the first and second shutters are closed, and wherein the rotational member includes a sidewall that contacts with at least one of the disc holders in such a manner as to prevent the at least one disc holder from being deformed in a radial direction of the disc while the first and second shutters are closed.
 30. A disc cartridge comprising: a cartridge body including a disc storage portion, a chucking opening and a head opening, wherein the disc storage portion has a disc window and a bottom and stores a disc, having first and second sides, therein so that the disc is rotatable in the disc storage portion and that the first side of the disc is exposed inside the disc window; the chucking opening is formed on the bottom of the disc storage portion so as to get the disc chucked externally; and the head opening is also formed on the bottom of the disc storage portion so as to allow a head, which reads and/or writes a signal from/on the second side of the disc, to access the second side of the disc; first and second shutters, provided on the bottom of the disc storage portion, for exposing or covering the head opening; and a rotational member, which is provided over the first and second shutters inside the disc storage portion and which is interlocked with the first and second shutters in such a manner as to open or close the first and second shutters when rotates inside the disc storage portion, wherein the cartridge body includes a rim, which is provided on the bottom of the disc storage portion so as to surround the chucking and head openings, and wherein the first and second shutters include respective concave portions on their back surfaces, which are opposed to the bottom of the disc storage portion, to receive the rim.
 31. A disc cartridge comprising: a cartridge body including a disc storage portion, a chucking opening and a head opening, wherein the disc storage portion has a disc window and a bottom and stores a disc, having first and second sides, therein so that the disc is rotatable in the disc storage portion and that the first side of the disc is exposed inside the disc window; the chucking opening is formed on the bottom of the disc storage portion so as to get the disc chucked externally; and the head opening is also formed on the bottom of the disc storage portion so as to allow a head, which reads and/or writes a signal from/on the second side of the disc, to access the second side of the disc; first and second shutters, provided on the bottom of the disc storage portion, for exposing or covering the head opening; and a rotational member, which is provided over the first and second shutters inside the disc storage portion and which is interlocked with the first and second shutters in such a manner as to open or close the first and second shutters when rotates inside the disc storage portion, wherein the cartridge body includes engaging means that is selectively engageable with a first or second disc stopper so that each of the first and second disc stoppers is attachable to the cartridge body, the first disc stopper being movable from a first position, at which the first disc stopper protrudes partially over the disc that is stored inside the disc storage portion, to a second position, at which the first disc stopper is not located over the disc, or vice versa, the second disc stopper being fixed at the first position.
 32. A disc cartridge comprising: a cartridge body including a disc storage portion, a chucking opening and a head opening, wherein the disc storage portion has a disc window and a bottom and stores a disc, having first and second sides, therein so that the disc is rotatable in the disc storage portion and that the first side of the disc is exposed inside the disc window; the chucking opening is formed on the bottom of the disc storage portion so as to get the disc chucked externally; and the head opening is also formed on the bottom of the disc storage portion so as to allow a head, which reads and/or writes a signal from/on the second side of the disc, to access the second side of the disc; first and second shutters, provided on the bottom of the disc storage portion, for exposing or covering the head opening; and a rotational member, which is provided over the first and second shutters inside the disc storage portion and which is interlocked with the first and second shutters in such a manner as to open or close the first and second shutters when rotates inside the disc storage portion, wherein the first and second shutters are disposed so as to be sandwiched between the rotational member and the bottom of the disc storage portion, and wherein the cartridge body includes a raised portion, which has a height that is approximately equal to the thickness of the first and second shutters, on the bottom of the disc storage portion.
 33. A disc drive, which is loaded with the disc cartridge according to one of claims 1 to 32 and which reads and/or writes a signal from/on the disc that is stored in the disc cartridge.
 34. A disc drive comprising: driving means for rotating a disc; a head for reading and/or writing a signal from/on the disc; a supporting structure for supporting the disc cartridge, which stores the disc therein as recited in one of claims 1, 6, 17 and 29, at a predetermined position with respect to the driving means; and a shutter opening/closing mechanism for opening the shutter of the disc cartridge and getting the disc released from the disc holder so that the disc is rotatable inside the disc storage portion of the disc cartridge.
 35. The disc drive of claim 34, further comprising a damper for mounting the disc onto the driving means.
 36. The disc drive of claim 35, wherein the supporting structure includes a positioning pin for fixing the disc cartridge at the predetermined position.
 37. The disc cartridge of claim 25, wherein the disc holder holds the disc in such a manner as not to contact with protruding ring provided on the second side of the disc in the vicinity clamp area.
 38. The disc cartridge of claim 37, wherein when the first and second shutters are closed, the disc holder holds the disc in such a manner as not to contact with neither a clamp area nor a region which is located between the clamp area and the center hole and which is apart from the edge of the center hole by 0.1 mm or more or in such a manner as not to contact with neither a clamp area nor a region which is located between the clamp area and the signal recording area and which is apart from the edge of the clamp area by 2 mm or less. 